Of course his work — or should that be hobby? —
isn't his only passion. He also enjoys other pleasures.
...
The following extract shows how aside p137 can be used for blogrolls and other side content on a blog:
A dolor sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex
ea commodo consequat. Duis aute irure dolor in reprehenderit in
voluptate velit esse cillum dolore eu fugiat nulla
pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
culpa qui officia deserunt mollit anim id est laborum.
Apples are fruit.
Apples are fruit.
Hello world.
The little kitten gently seated himself on a piece of
carpet. Later in his life, this would be referred to as the time the
cat sat on the mat.
Dudley was ninety-two, in his second life, and fast approaching
time for another rejuvenation. Despite his body having the physical
age of a standard fifty-year-old, the prospect of a long degrading
campaign within academia was one he regarded with dread. For a
supposedly advanced civilization, the Intersolar Commonwearth could be
appallingly backward at times, not to mention cruel.
The Carlton AllLander drove Dudley home just after dawn. Like the
astronomer, the vehicle was old and worn, but perfectly capable of
doing its job. It had a cheap diesel engine, common enough on a
semi-frontier world like Gralmond, although its drive array was a
thoroughly modern photoneural processor. With its high suspension and
deep-tread tyres it could plough along the dirt track to the
observatory in all weather and seasons, including the metre-deep snow
of Gralmond's winters.
4.5.3 The pre element
Categories
Flow content p91 .
formatBlock candidate p536 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
interface HTMLPreElement : HTMLElement {};
The pre p150 element represents p638 a block of preformatted text, in which structure is represented by typographic
conventions rather than by elements.
Note: In the HTML syntax p547 , a leading newline character immediately following the pre p150
element start tag is stripped.
Some examples of cases where the pre p150 element could be used:
•
Including an e-mail, with paragraphs indicated by blank lines, lists indicated by lines prefixed with a
bullet, and so on.
•
Including fragments of computer code, with structure indicated according to the conventions of that
language.
•
Displaying ASCII art.
Note: Authors are encouraged to consider how preformatted text will be experienced when
the formatting is lost, as will be the case for users of speech synthesizers, braille displays,
and the like. For cases like ASCII art, it is likely that an alternative presentation, such as a
textual description, would be more universally accessible to the readers of the document.
To represent a block of computer code, the pre p150 element can be used with a code p171 element; to represent a
block of computer output the pre p150 element can be used with a samp p172 element. Similarly, the kbd p173 element
can be used within a pre p150 element to indicate text that the user is to enter.
In the following snippet, a sample of computer code is presented.
My mistress' eyes are nothing like the sun,
151
t3yw 12 points 1 hour agoI bet a narwhal would love that.
I bet a narwhal would love that.
Dude narwhals don't eat bacon.
t3yw 15 points 1 hour ago
I bet a narwhal would love that.
Dude narwhals don't eat bacon.
Next thing you'll be saying they don't get capes and wizard
hats either!
boing -5 points 1 hour agonarwhals are worse than ceiling cat
fred 1 points 23 minutes agoI bet a narwhal would love that.
I bet they'd love to peel a banana too.
Note: Examples of how to represent a conversation p395 are shown in a later section; it is not
appropriate to use the cite p165 and blockquote p151 elements for this purpose.
4.5.5 The ol element
Categories
Flow content p91 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Zero or more li p154 elements.
Content attributes:
Global attributes p82
reversed p152
start p153
DOM interface:
interface HTMLOListElement : HTMLElement {
attribute boolean reversed;
attribute long start;
};
The ol p152 element represents p638 a list of items, where the items have been intentionally ordered, such that
changing the order would change the meaning of the document.
The items of the list are the li p154 element child nodes of the ol p152 element, in tree order p27 .
The reversed attribute is a boolean attribute p34 . If present, it indicates that the list is a descending list (..., 3, 2, 1).
If the attribute is omitted, the list is an ascending list (1, 2, 3, ...).
152
The start attribute, if present, must be a valid integer p35 giving the ordinal value of the first list item.
If the start p153 attribute is present, user agents must parse it as an integer p35 , in order to determine the
attribute's value. The default value, used if the attribute is missing or if the value cannot be converted to a
number according to the referenced algorithm, is 1 if the element has no reversed p152 attribute, and is the
number of child li p154 elements otherwise.
The first item in the list has the ordinal value given by the ol p152 element's start p153 attribute, unless that li p154
element has a value p154 attribute with a value that can be successfully parsed, in which case it has the ordinal
value given by that value p154 attribute.
Each subsequent item in the list has the ordinal value given by its value p154 attribute, if it has one, or, if it doesn't,
the ordinal value of the previous item, plus one if the reversed p152 is absent, or minus one if it is present.
The reversed IDL attribute must reflect p57 the value of the reversed p152 content attribute.
The start IDL attribute must reflect p57 the value of the start p153 content attribute.
The following markup shows a list where the order matters, and where the ol p152 element is therefore
appropriate. Compare this list to the equivalent list in the ul p153 section to see an example of the same
items using the ul p153 element.
I have lived in the following countries (given in the order of when
I first lived there):
Switzerland
United Kingdom
United States
Norway
Note how changing the order of the list changes the meaning of the document. In the following example,
changing the relative order of the first two items has changed the birthplace of the author:
I have lived in the following countries (given in the order of when
I first lived there):
United Kingdom
Switzerland
United States
Norway
4.5.6 The ul element
Categories
Flow content p91 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Zero or more li p154 elements.
Content attributes:
Global attributes p82
DOM interface:
interface HTMLUListElement : HTMLElement {};
The ul p153 element represents p638 a list of items, where the order of the items is not important — that is, where
changing the order would not materially change the meaning of the document.
The items of the list are the li p154 element child nodes of the ul p153 element.
The following markup shows a list where the order does not matter, and where the ul p153 element is
therefore appropriate. Compare this list to the equivalent list in the ol p152 section to see an example of the
same items using the ol p152 element.
I have lived in the following countries:
Norway
153
Switzerland
United Kingdom
United States
Note that changing the order of the list does not change the meaning of the document. The items in the
snippet above are given in alphabetical order, but in the snippet below they are given in order of the size of
their current account balance in 2007, without changing the meaning of the document whatsoever:
I have lived in the following countries:
Switzerland
Norway
United Kingdom
United States
4.5.7 The li element
Categories
None.
Contexts in which this element may be used:
Inside ol p152 elements.
Inside ul p153 elements.
Inside menu p372 elements.
Content model:
Flow content p91 .
Content attributes:
Global attributes p82
If the element is a child of an ol p152 element: value p154
DOM interface:
interface HTMLLIElement : HTMLElement {
attribute long value;
};
The li p154 element represents p638 a list item. If its parent element is an ol p152 , ul p153 , or menu p372 element, then the
element is an item of the parent element's list, as defined for those elements. Otherwise, the list item has no
defined list-related relationship to any other li p154 element.
The value attribute, if present, must be a valid integer p35 giving the ordinal value of the list item.
If the value p154 attribute is present, user agents must parse it as an integer p35 , in order to determine the
attribute's value. If the attribute's value cannot be converted to a number, the attribute must be treated as if it
was absent. The attribute has no default value.
The value p154 attribute is processed relative to the element's parent ol p152 element (q.v.), if there is one. If there is
not, the attribute has no effect.
The value IDL attribute must reflect p57 the value of the value p154 content attribute.
The following example, the top ten movies are listed (in reverse order). Note the way the list is given a title
by using a figure p158 element and its figcaption p159 element.
The top 10 movies of all time
Josie and the Pussycats , 2001Црна мачка, бели мачор , 1998A Bug's Life , 1998Toy Story , 1995Monsters, Inc , 2001Cars , 2006Toy Story 2 , 1999Finding Nemo , 2003The Incredibles , 2004Ratatouille , 2007
The markup could also be written as follows, using the reversed p152 attribute on the ol p152 element:
The top 10 movies of all time
Josie and the Pussycats , 2001Црна мачка, бели мачор , 1998A Bug's Life , 1998Toy Story , 1995Monsters, Inc , 2001Cars , 2006Toy Story 2 , 1999Finding Nemo , 2003The Incredibles , 2004Ratatouille , 2007
Note: If the li p154 element is the child of a menu p372 element and itself has a child that defines a
command p376 , then the li p154 element will match the :enabled p398 and :disabled p398 pseudoclasses in the same way as the first such child element does.
4.5.8 The dl element
Categories
Flow content p91 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Zero or more groups each consisting of one or more dt p157 elements followed by one or more dd p157
elements.
Content attributes:
Global attributes p82
DOM interface:
interface HTMLDListElement : HTMLElement {};
The dl p155 element represents p638 an association list consisting of zero or more name-value groups (a description
list). Each group must consist of one or more names (dt p157 elements) followed by one or more values (dd p157
elements). Within a single dl p155 element, there should not be more than one dt p157 element for each name.
Name-value groups may be terms and definitions, metadata topics and values, or any other groups of name-value
data.
The values within a group are alternatives; multiple paragraphs forming part of the same value must all be given
within the same dd p157 element.
The order of the list of groups, and of the names and values within each group, may be significant.
If a dl p155 element is empty, it contains no groups.
If a dl p155 element contains non-whitespace p89 text nodes p27 , or elements other than dt p157 and dd p157 , then those
elements or text nodes p27 do not form part of any groups in that dl p155 .
If a dl p155 element contains only dt p157 elements, then it consists of one group with names but no values.
If a dl p155 element contains only dd p157 elements, then it consists of one group with values but no names.
If a dl p155 element starts with one or more dd p157 elements, then the first group has no associated name.
If a dl p155 element ends with one or more dt p157 elements, then the last group has no associated value.
155
Note: When a dl p155 element doesn't match its content model, it is often due to accidentally
using dd p157 elements in the place of dt p157 elements and vice versa. Conformance checkers can
spot such mistakes and might be able to advise authors how to correctly use the markup.
In the following example, one entry ("Authors") is linked to two values ("John" and "Luke").
Authors
John
Luke
Editor
Frank
In the following example, one definition is linked to two terms.
color
colour
A sensation which (in humans) derives from the ability of
the fine structure of the eye to distinguish three differently
filtered analyses of a view.
The following example illustrates the use of the dl p155 element to mark up metadata of sorts. At the end of
the example, one group has two metadata labels ("Authors" and "Editors") and two values ("Robert
Rothman" and "Daniel Jackson").
Last modified time
2004-12-23T23:33Z
Recommended update interval
60s
Authors
Editors
Robert Rothman
Daniel Jackson
The following example shows the dl p155 element used to give a set of instructions. The order of the
instructions here is important (in the other examples, the order of the blocks was not important).
Determine the victory points as follows (use the
first matching case):
If you have exactly five gold coins
You get five victory points
If you have one or more gold coins, and you have one or more silver coins
You get two victory points
If you have one or more silver coins
You get one victory point
Otherwise
You get no victory points
The following snippet shows a dl p155 element being used as a glossary. Note the use of dfn p167 to indicate
the word being defined.
Apartment , n.An execution context grouping one or more threads with one or
more COM objects.
Flat , n.A deflated tire.
Home , n.The user's login directory.
Note: The dl p155 element is inappropriate for marking up dialogue. Examples of how to mark up
dialogue p395 are shown below.
156
4.5.9 The dt element
Categories
None.
Contexts in which this element may be used:
Before dd p157 or dt p157 elements inside dl p155 elements.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The dt p157 element represents p638 the term, or name, part of a term-description group in a description list (dl p155
element).
Note: The dt p157 element itself, when used in a dl p155 element, does not indicate that its
contents are a term being defined, but this can be indicated using the dfn p167 element.
This example shows a list of frequently asked questions (a FAQ) marked up using the dt p157 element for
questions and the dd p157 element for answers.
FAQ
What do we want?
Our data.
When do we want it?
Now.
Where is it?
We are not sure.
4.5.10 The dd element
Categories
None.
Contexts in which this element may be used:
After dt p157 or dd p157 elements inside dl p155 elements.
Content model:
Flow content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The dd p157 element represents p638 the description, definition, or value, part of a term-description group in a
description list (dl p155 element).
A dl p155 can be used to define a vocabulary list, like in a dictionary. In the following example, each entry,
given by a dt p157 with a dfn p167 , has several dd p157 s, showing the various parts of the definition.
happiness /'hæ p. nes/
n. The state of being happy.
Good fortune; success. Oh happiness ! It worked!
rejoice /ri jois'/
v.intr. v.tr.
4.5.11 The figure element
Categories
Flow content p91 .
Sectioning root p144 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Either: One figcaption p159 element followed by flow content p91 .
Or: Flow content p91 followed by one figcaption p159 element.
Or: Flow content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The figure p158 element represents p638 some flow content p91 , optionally with a caption, that is self-contained and is
typically referenced as a single unit from the main flow of the document.
The element can thus be used to annotate illustrations, diagrams, photos, code listings, etc, that are referred to
from the main content of the document, but that could, without affecting the flow of the document, be moved
away from that primary content, e.g. to the side of the page, to dedicated pages, or to an appendix.
The first figcaption p159 element child of the element, if any, represents the caption of the figure p158 element's
contents. If there is no child figcaption p159 element, then there is no caption.
This example shows the figure p158 element to mark up a code listing.
In listing 4 we see the primary core interface
API declaration.
Listing 4. The primary core interface API declaration.
interface PrimaryCore {
boolean verifyDataLine();
void sendData(in sequence<byte> data);
void initSelfDestruct();
}
The API is designed to use UTF-8.
Here we see a figure p158 element to mark up a photo.
Bubbles at work
In this example, we see an image that is not a figure, as well as an image and a video that are.
Malinko's comics
This case centered on some sort of "intellectual property"
infringement related to a comic (see Exhibit A). The suit started
after a trailer ending with these words:
...was aired. A lawyer, armed with a Bigger Notebook, launched a
preemptive strike using snowballs. A complete copy of the trailer is
included with Exhibit B.
158
Exhibit A. The alleged rough copy comic.
Exhibit B. The Rough Copy trailer.
The case was resolved out of court.
Here, a part of a poem is marked up using figure p158 .
'Twas brillig, and the slithy toves
Jabberwocky (first verse). Lewis Carroll,
1832-98
In this example, which could be part of a much larger work discussing a castle, the figure has three images
in it.
The castle through the ages: 1423, 1858, and 1999
respectively.
4.5.12 The figcaption element
Categories
None.
Contexts in which this element may be used:
As the first or last child of a figure p158 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The figcaption p159 element represents p638 a caption or legend for the rest of the contents of the figcaption p159
element's parent figure p158 element, if any.
4.5.13 The div element
Categories
Flow content p91 .
formatBlock candidate p536 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Flow content p91 .
159
Content attributes:
Global attributes p82
DOM interface:
interface HTMLDivElement : HTMLElement {};
The div p159 element has no special meaning at all. It represents p638 its children. It can be used with the class p86 ,
lang p85 , and title p84 attributes to mark up semantics common to a group of consecutive elements.
Note: Authors are strongly encouraged to view the div p159 element as an element of last
resort, for when no other element is suitable. Use of the div p159 element instead of more
appropriate elements leads to poor accessibility for readers and poor maintainability for
authors.
For example, a blog post would be marked up using article p136 , a chapter using section p133 , a page's
navigation aids using nav p134 , and a group of form controls using fieldset p300 .
On the other hand, div p159 elements can be useful for stylistic purposes or to wrap multiple paragraphs
within a section that are all to be annotated in a similar way. In the following example, we see div p159
elements used as a way to set the language of two paragraphs at once, instead of setting the language on
the two paragraph elements separately:
My use of language and my cats
My cat's behavior hasn't changed much since her absence, except
that she plays her new physique to the neighbors regularly, in an
attempt to get pets.
My other cat, coloured black and white, is a sweetie. He followed
us to the pool today, walking down the pavement with us. Yesterday
he apparently visited our neighbours. I wonder if he recognises that
their flat is a mirror image of ours.
Hm, I just noticed that in the last paragraph I used British
English. But I'm supposed to write in American English. So I
shouldn't say "pavement" or "flat" or "colour"...
I should say "sidewalk" and "apartment" and "color"!
4.6 Text-level semantics
4.6.1 The a element
Categories
Flow content p91 .
When the element only contains phrasing content p91 : phrasing content p91 .
Interactive content p92 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Transparent p93 , but there must be no interactive content p92 descendant.
Content attributes:
Global attributes p82
href p383
target p384
ping p384
rel p384
media p384
hreflang p384
type p384
160
DOM interface:
interface HTMLAnchorElement : HTMLElement {
stringifier attribute DOMString href;
attribute DOMString target;
attribute DOMString ping;
attribute
readonly attribute
attribute
attribute
attribute
DOMString rel;
DOMTokenList relList;
DOMString media;
DOMString hreflang;
DOMString type;
attribute DOMString text;
// URL decomposition IDL attributes
attribute DOMString protocol;
attribute DOMString host;
attribute DOMString hostname;
attribute DOMString port;
attribute DOMString pathname;
attribute DOMString search;
attribute DOMString hash;
};
If the a p160 element has an href p383 attribute, then it represents p638 a hyperlink p383 (a hypertext anchor).
If the a p160 element has no href p383 attribute, then the element represents p638 a placeholder for where a link might
otherwise have been placed, if it had been relevant.
The target p384 , ping p384 , rel p384 , media p384 , hreflang p384 , and type p384 attributes must be omitted if the href p383
attribute is not present.
If a site uses a consistent navigation toolbar on every page, then the link that would normally link to the
page itself could be marked up using an a p160 element:
Home
News
Examples
Legal
The href p383 , target p384 and ping p384 attributes affect what happens when users follow hyperlinks p384 created
using the a p160 element. The rel p384 , media p384 , hreflang p384 , and type p384 attributes may be used to indicate to
the user the likely nature of the target resource before the user follows the link.
The activation behavior p93 of a p160 elements that represent hyperlinks p383 is to run the following steps:
1.
If the DOMActivate p31 event in question is not trusted p27 (i.e. a click() p508 method call was the reason
for the event being dispatched), and the a p160 element's target p384 attribute is such that applying the
rules for choosing a browsing context given a browsing context name p442 , using the value of the
target p384 attribute as the browsing context name, would result in there not being a chosen browsing
context, then raise an INVALID_ACCESS_ERR p70 exception and abort these steps.
2.
If the target of the click p31 event is an img p186 element with an ismap p189 attribute specified, then
server-side image map processing must be performed, as follows:
1.
If the DOMActivate p31 event was dispatched as the result of a real pointing-device-triggered
click p31 event on the img p186 element, then let x be the distance in CSS pixels from the left
edge of the image's left border, if it has one, or the left edge of the image otherwise, to the
location of the click, and let y be the distance in CSS pixels from the top edge of the image's
top border, if it has one, or the top edge of the image otherwise, to the location of the click.
Otherwise, let x and y be zero.
161
2.
3.
Let the hyperlink suffix be a U+003F QUESTION MARK character, the value of x expressed as
a base-ten integer using ASCII digits, a U+002C COMMA character (,), and the value of y
expressed as a base-ten integer using ASCII digits. ASCII digits are the characters in the range
U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
Finally, the user agent must follow the hyperlink p384 defined by the a p160 element. If the steps above
defined a hyperlink suffix p162 , then take that into account when following the hyperlink.
This box is non-normative. Implementation requirements are given below this box.
a . text
p162
Same as textContent p31 .
The IDL attributes href, ping, target, rel, media, hreflang, and type, must reflect p57 the respective content
attributes of the same name.
The IDL attribute relList must reflect p57 the rel p384 content attribute.
The text IDL attribute, on getting, must return the same value as the textContent p31 IDL attribute on the
element, and on setting, must act as if the textContent p31 IDL attribute on the element had been set to the new
value.
The a p160 element also supports the complement of URL decomposition IDL attributes p53 , protocol, host, port,
hostname, pathname, search, and hash. These must follow the rules given for URL decomposition IDL attributes,
with the input p54 being the result of resolving p51 the element's href p383 attribute relative to the element, if there is
such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action p54
being the same as setting the element's href p383 attribute to the new output value.
The a p160 element may be wrapped around entire paragraphs, lists, tables, and so forth, even entire
sections, so long as there is no interactive content within (e.g. buttons or other links). This example shows
how this can be used to make an entire advertising block into a link:
4.6.2 The em element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The em p162 element represents p638 stress emphasis of its contents.
162
The level of emphasis that a particular piece of content has is given by its number of ancestor em p162 elements.
The placement of emphasis changes the meaning of the sentence. The element thus forms an integral part of the
content. The precise way in which emphasis is used in this way depends on the language.
These examples show how changing the emphasis changes the meaning. First, a general statement of fact,
with no emphasis:
Cats are cute animals.
By emphasizing the first word, the statement implies that the kind of animal under discussion is in question
(maybe someone is asserting that dogs are cute):
Cats are cute animals.
Moving the emphasis to the verb, one highlights that the truth of the entire sentence is in question (maybe
someone is saying cats are not cute):
Cats are cute animals.
By moving it to the adjective, the exact nature of the cats is reasserted (maybe someone suggested cats
were mean animals):
Cats are cute animals.
Similarly, if someone asserted that cats were vegetables, someone correcting this might emphasize the last
word:
Cats are cute animals .
By emphasizing the entire sentence, it becomes clear that the speaker is fighting hard to get the point
across. This kind of emphasis also typically affects the punctuation, hence the exclamation mark here.
Cats are cute animals!
Anger mixed with emphasizing the cuteness could lead to markup such as:
Cats are cute animals!
The em p162 element isn't a generic "italics" element. Sometimes, text is intended to stand out
from the rest of the paragraph, as if it was in a different mood or voice. For this, the i p174
element is more appropriate.
The em p162 element also isn't intended to convey importance; for that purpose, the strong p163
element is more appropriate.
4.6.3 The strong element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The strong p163 element represents p638 strong importance for its contents.
The relative level of importance of a piece of content is given by its number of ancestor strong p163 elements; each
strong p163 element increases the importance of its contents.
Changing the importance of a piece of text with the strong p163 element does not change the meaning of the
sentence.
Here is an example of a warning notice in a game, with the various parts marked up according to how
important they are:
163
Warning. This dungeon is dangerous.
Avoid the ducks. Take any gold you find.
Do not take any of the diamonds ,
they are explosive and will destroy anything within
ten meters.
4.6.4 The small element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The small p164 element represents p638 side comments such as small print.
Note: Small print typically features disclaimers, caveats, legal restrictions, or copyrights.
Small print is also sometimes used for attribution, or for satisfying licensing requirements.
Note: The small p164 element does not "de-emphasize" or lower the importance of text
emphasized by the em p162 element or marked as important with the strong p163 element. To mark
text as not emphasized or important, simply do not mark it up with the em p162 or strong p163
elements respectively.
The small p164 element should not be used for extended spans of text, such as multiple paragraphs, lists, or
sections of text. It is only intended for short runs of text. The text of a page listing terms of use, for instance,
would not be a suitable candidate for the small p164 element: in such a case, the text is not a side comment, it is
the main content of the page.
In this example the footer contains contact information and a copyright notice.
In this second example, the small p164 element is used for a side comment in an article.
Example Corp today announced record profits for the
second quarter (Full Disclosure: Foo News is a subsidiary of
Example Corp) , leading to speculation about a third quarter
merger with Demo Group.
This is distinct from a sidebar, which might be multiple paragraphs long and is removed from the main flow
of text. In the following example, we see a sidebar from the same article. This sidebar also has small print,
indicating the source of the information in the sidebar.
Example Corp
This company mostly creates small software and Web
sites.
The Example Corp company mission is "To provide entertainment
and news on a sample basis".
Information obtained from example.com home
page.
164
In this last example, the small p164 element is marked as being important small print.
Continued use of this service will result in a
kiss.
4.6.5 The cite element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The cite p165 element represents p638 the title of a work (e.g. a book, a paper, an essay, a poem, a score, a song, a
script, a film, a TV show, a game, a sculpture, a painting, a theatre production, a play, an opera, a musical, an
exhibition, a legal case report, etc). This can be a work that is being quoted or referenced in detail (i.e. a citation),
or it can just be a work that is mentioned in passing.
A person's name is not the title of a work — even if people call that person a piece of work — and the element
must therefore not be used to mark up people's names. (In some cases, the b p175 element might be appropriate for
names; e.g. in a gossip article where the names of famous people are keywords rendered with a different style to
draw attention to them. In other cases, if an element is really needed, the span p180 element can be used.)
This next example shows a typical use of the cite p165 element:
My favorite book is The Reality Dysfunction by
Peter F. Hamilton. My favorite comic is Pearls Before
Swine by Stephan Pastis. My favorite track is Jive
Samba by the Cannonball Adderley Sextet.
This is correct usage:
According to the Wikipedia article HTML , as it
stood in mid-February 2008, leaving attribute values unquoted is
unsafe. This is obviously an over-simplification.
The following, however, is incorrect usage, as the cite p165 element here is containing far more than the title
of the work:
According to the Wikipedia article on HTML , as it
stood in mid-February 2008, leaving attribute values unquoted is
unsafe. This is obviously an over-simplification.
The cite p165 element is obviously a key part of any citation in a bibliography, but it is only used to mark the
title:
Universal Declaration of Human Rights , United Nations,
December 1948. Adopted by General Assembly resolution 217 A (III).
Note: A citation is not a quote (for which the q p166 element is appropriate).
This is incorrect usage, because cite p165 is not for quotes:
This is wrong! , said Ian.
This is also incorrect usage, because a person is not a work:
This is still wrong! , said Ian .
The correct usage does not use a cite p165 element:
This is correct , said Ian.
165
As mentioned above, the b p175 element might be relevant for marking names as being keywords in certain
kinds of documents:
And then Ian said this might be right, in a
gossip column, maybe! .
4.6.6 The q element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
cite p166
DOM interface:
Uses HTMLQuoteElement p151 .
The q p166 element represents p638 some phrasing content p91 quoted from another source.
Quotation punctuation (such as quotation marks) that is quoting the contents of the element must not appear
immediately before, after, or inside q p166 elements; they will be inserted into the rendering by the user agent.
Content inside a q p166 element must be quoted from another source, whose address, if it has one, should be cited
in the cite attribute. The source may be fictional, as when quoting characters in a novel or screenplay.
If the cite p166 attribute is present, it must be a valid URL p51 . To obtain the corresponding citation link, the value of
the attribute must be resolved p51 relative to the element. User agents should allow users to follow such citation
links.
The q p166 element must not be used in place of quotation marks that do not represent quotes; for example, it is
inappropriate to use the q p166 element for marking up sarcastic statements.
The use of q p166 elements to mark up quotations is entirely optional; using explicit quotation punctuation without
q p166 elements is just as correct.
Here is a simple example of the use of the q p166 element:
The man said Things that are impossible just take
longer . I disagreed with him.
Here is an example with both an explicit citation link in the q p166 element, and an explicit citation outside:
The W3C page About W3C says the W3C's
mission is To lead the
World Wide Web to its full potential by developing protocols and
guidelines that ensure long-term growth for the Web . I
disagree with this mission.
In the following example, the quotation itself contains a quotation:
In Example One , he writes The man
said Things that are impossible just take longer . I
disagreed with him . Well, I disagree even more!
In the following example, quotation marks are used instead of the q p166 element:
His best argument was ❝I disagree❞, which
I thought was laughable.
In the following example, there is no quote — the quotation marks are used to name a word. Use of the q p166
element in this case would be inappropriate.
The word "ineffable" could have been used to describe the disaster
resulting from the campaign's mismanagement.
166
4.6.7 The dfn element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but there must be no dfn p167 element descendants.
Content attributes:
Global attributes p82
Also, the title p167 attribute has special semantics on this element.
DOM interface:
Uses HTMLElement p81 .
The dfn p167 element represents p638 the defining instance of a term. The paragraph p93 , description list group p155 , or
section p91 that is the nearest ancestor of the dfn p167 element must also contain the definition(s) for the term p167
given by the dfn p167 element.
Defining term: If the dfn p167 element has a title attribute, then the exact value of that attribute is the term
being defined. Otherwise, if it contains exactly one element child node and no child text nodes p27 , and that child
element is an abbr p167 element with a title p167 attribute, then the exact value of that attribute is the term being
defined. Otherwise, it is the exact textContent p31 of the dfn p167 element that gives the term being defined.
If the title p167 attribute of the dfn p167 element is present, then it must contain only the term being defined.
Note: The title p84 attribute of ancestor elements does not affect dfn p167 elements.
An a p160 element that links to a dfn p167 element represents an instance of the term defined by the dfn p167 element.
In the following fragment, the term "GDO" is first defined in the first paragraph, then used in the second.
The GDO
Teal'c activated his GDO
and so Hammond ordered the iris to be opened.
With the addition of an a p160 element, the reference can be made explicit:
The GDO
Teal'c activated his GDO
4.6.8 The abbr element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
Also, the title p167 attribute has special semantics on this element.
DOM interface:
Uses HTMLElement p81 .
The abbr p167 element represents p638 an abbreviation or acronym, optionally with its expansion. The title attribute
may be used to provide an expansion of the abbreviation. The attribute, if specified, must contain an expansion of
the abbreviation, and nothing else.
167
The paragraph below contains an abbreviation marked up with the abbr p167 element. This paragraph defines
the term p167 "Web Hypertext Application Technology Working Group".
The WHATWG
An alternative way to write this would be:
The Web Hypertext Application Technology
Working Group (WHATWG )
is a loose unofficial collaboration of Web browser manufacturers and
interested parties who wish to develop new technologies designed to
allow authors to write and deploy Applications over the World Wide
Web.
This paragraph has two abbreviations. Notice how only one is defined; the other, with no expansion
associated with it, does not use the abbr p167 element.
The
WHATWG
started working on HTML5 in 2004.
This paragraph links an abbreviation to its definition.
The WHATWG
This paragraph marks up an abbreviation without giving an expansion, possibly as a hook to apply styles for
abbreviations (e.g. smallcaps).
Philip` and Dashiva both denied that they were going to
get the issue counts from past revisions of the specification to
backfill the WHATWG issue graph.
If an abbreviation is pluralized, the expansion's grammatical number (plural vs singular) must match the
grammatical number of the contents of the element.
Here the plural is outside the element, so the expansion is in the singular:
Two WG s worked on
this specification: the WHATWG and the
HTMLWG .
Here the plural is inside the element, so the expansion is in the plural:
Two WGs worked on
this specification: the WHATWG and the
HTMLWG .
Abbreviations do not have to be marked up using this element. It is expected to be useful in the following cases:
•
Abbreviations for which the author wants to give expansions, where using the abbr p167 element with a
title p84 attribute is an alternative to including the expansion inline (e.g. in parentheses).
•
Abbreviations that are likely to be unfamiliar to the document's readers, for which authors are
encouraged to either mark up the abbreviation using a abbr p167 element with a title p84 attribute or
include the expansion inline in the text the first time the abbreviation is used.
•
Abbreviations whose presence needs to be semantically annotated, e.g. so that they can be identified
from a style sheet and given specific styles, for which the abbr p167 element can be used without a
title p84 attribute.
Providing an expansion in a title p84 attribute once will not necessarily cause other abbr p167 elements in the same
document with the same contents but without a title p84 attribute to behave as if they had the same expansion.
Every abbr p167 element is independent.
4.6.9 The time element
168
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but there must be no time p168 element descendants.
Content attributes:
Global attributes p82
datetime p169
pubdate p169
DOM interface:
interface HTMLTimeElement : HTMLElement {
attribute DOMString dateTime;
attribute boolean pubDate;
readonly attribute Date valueAsDate;
};
The time p168 element represents p638 either a time on a 24 hour clock, or a precise date in the proleptic Gregorian
calendar, optionally with a time and a time-zone offset. [GREGORIAN] p701
This element is intended as a way to encode modern dates and times in a machine-readable way so that, for
example, user agents can offer to add birthday reminders or scheduled events to the user's calendar.
The time p168 element is not intended for encoding times for which a precise date or time
cannot be established. For example, it would be inappropriate for encoding times like "one
millisecond after the big bang", "the early part of the Jurassic period", or "a winter around 250
BCE".
For dates before the introduction of the Gregorian calendar, authors are encouraged to not
use the time p168 element, or else to be very careful about converting dates and times from the
period to the Gregorian calendar. This is complicated by the manner in which the Gregorian
calendar was phased in, which occurred at different times in different countries, ranging from
partway through the 16th century all the way to early in the 20th.
The pubdate attribute is a boolean attribute p34 . If specified, it indicates that the date and time given by the
element is the publication date and time of the nearest ancestor article p136 element, or, if the element has no
ancestor article p136 element, of the document as a whole. If the element has a pubdate p169 attribute specified,
then the element needs a date. For each article p136 element, there must no more than one time p168 element
with a pubdate p169 attribute whose nearest ancestor is that article p136 element. Furthermore, for each
Document p31 , there must be no more than one time p168 element with a pubdate p169 attribute that does not have an
ancestor article p136 element.
The datetime attribute, if present, gives the date or time being specified. Otherwise, the date or time is given by
the element's contents.
If the element needs a date p169 , and the datetime p169 attribute is present, then the attribute's value must be a
valid date string with optional time p46 .
If the element needs a date p169 , but the datetime p169 attribute is not present, then the element's textContent p31
must be a valid date string in content with optional time p46 .
If the element does not need a date, and the datetime p169 attribute is present, then the attribute's value must be
a valid date or time string p46 .
If the element does not need a date, but the datetime p169 attribute is not present, then the element's
textContent p31 must be a valid date or time string in content p46 .
The date, if any, must be expressed using the Gregorian calendar.
If the datetime p169 attribute is present, the user agent should convey the attribute's value to the user when
rendering the element.
The time p168 element can be used to encode dates, for example in Microformats. The following shows a
hypothetical way of encoding an event using a variant on hCalendar that uses the time p168 element:
169
(The end date is encoded as one day after the last date of the event because in the iCalendar format, end
dates are exclusive, not inclusive.)
The time p168 element is not necessary for encoding dates or times. In the following snippet, the time is
encoded using time p168 , so that it can be restyled (e.g. using XBL2) to match local conventions, while the
year is not marked up at all, since marking it up would not be particularly useful.
I usually have a snack at 16:00 .
I've liked model trains since at least 1983.
Using a styling technology that supports restyling times, the first paragraph from the above snippet could
be rendered as follows:
I usually have a snack at 4pm.
Or it could be rendered as follows:
I usually have a snack at 16h00.
The dateTime IDL attribute must reflect p57 the datetime p169 content attribute.
The pubDate IDL attribute must reflect p57 the pubdate p169 content attribute.
User agents, to obtain the date, time, and time-zone offset represented by a time p168 element, must follow
these steps:
1.
If the datetime p169 attribute is present, then use the rules to parse a date or time string p47 with the flag
in attribute from the value of that attribute, and let the result be result.
2.
Otherwise, use the rules to parse a date or time string p47 with the flag in content from the element's
textContent p31 , and let the result be result.
3.
If result is empty (because the parsing failed), then the date p170 is unknown, the time p170 is unknown,
and the time-zone offset p170 is unknown.
4.
Otherwise: if result contains a date, then that is the date p170 ; if result contains a time, then that is the
time p170 ; and if result contains a time-zone offset, then the time-zone offset is the element's time-zone
offset p170 . (A time-zone offset can only be present if both a date and a time are also present.)
This box is non-normative. Implementation requirements are given below this box.
time . valueAsDate
p170
Returns a Date object representing the specified date and time.
The valueAsDate IDL attribute must return either null or a new Date object initialised to the relevant value as
defined by the following list:
If the date p170 is known but the time p170 is not
The time corresponding to midnight UTC (i.e. the first second) of the given date p170 .
If the time p170 is known but the date p170 is not
The time corresponding to the given time p170 of 1970-01-01, with the time zone UTC.
If both the date p170 and the time p170 are known
The time corresponding to the date p170 and time p170 , with the given time-zone offset p170 .
If neither the date p170 nor the time p170 are known
The null value.
When a Date object is to be returned, a new one must be constructed.
In the following snippet:
Our first date was a Saturday .
170
...the time p168 element's valueAsDate p170 attribute would have the value 1,158,969,600,000ms.
In the following snippet:
Many people get up at 08:00 .
...the time p168 element's valueAsDate p170 attribute would have the value 28,800,000ms.
In this example, an article's publication date is marked up using time p168 :
Small tasks
I put a bike bell on his bike.
Here is another way that could be marked up:
Small tasks
I put a bike bell on his bike.
Here is the same thing but with the time included. Because the element is empty, it will be replaced in the
rendering with a more readable version of the date and time given.
Small tasks
I put a bike bell on his bike.
4.6.10 The code element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The code p171 element represents p638 a fragment of computer code. This could be an XML element name, a
filename, a computer program, or any other string that a computer would recognize.
Although there is no formal way to indicate the language of computer code being marked up, authors who wish to
mark code p171 elements with the language used, e.g. so that syntax highlighting scripts can use the right rules,
may do so by adding a class prefixed with "language-" to the element.
The following example shows how the element can be used in a paragraph to mark up element names and
computer code, including punctuation.
The code element represents a fragment of computer
code.
When you call the activate() method on the
robotSnowman object, the eyes glow.
The example
the start of a
keyword, which
(full stop) to
below uses the begin keyword to indicate
statement block. It is paired with an end
is followed by the . punctuation character
indicate the end of the program.
171
The following example shows how a block of code could be marked up using the pre p150 and code p171
elements.
var i: Integer;
begin
i := 1;
end.If there are n pipes leading to the ice
cream factory then I expect at least n
flavors of ice cream to be available for purchase!
For mathematics, in particular for anything beyond the simplest of expressions, MathML is more appropriate.
However, the var p172 element can still be used to refer to specific variables that are then mentioned in MathML
expressions.
In this example, an equation is shown, with a legend that references the variables in the equation. The
expression itself is marked up with MathML, but the variables are mentioned in the figure's legend using
var p172 .
a
=
b 2 +
c 2
Using Pythagoras' theorem to solve for the hypotenuse a of
a triangle with sides b and c
4.6.12 The samp element
Categories
Flow content p91 .
Phrasing content p91 .
172
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The samp p172 element represents p638 (sample) output from a program or computing system.
Note: See the pre p150 and kbd p173 elements for more details.
This example shows the samp p172 element being used inline:
The computer said Too much cheese in tray
two but I didn't know what that meant.
This second example shows a block of sample output. Nested samp p172 and kbd p173 elements allow for the
styling of specific elements of the sample output using a style sheet.
jdoe@mowmow:~$ ssh demo.example.com
Last login: Tue Apr 12 09:10:17 2005 from mowmow.example.com on pts/1
Linux demo 2.6.10-grsec+gg3+e+fhs6b+nfs+gr0501+++p3+c4a+gr2b-reslog-v6.189 #1 SMP Tue
Feb 1 11:22:36 PST 2005 i686 unknown
jdoe@demo:~$ _ To make George eat an apple, press Shift +F3
In this second example, the user is told to pick a particular menu item. The outer kbd p173 element marks up
a block of input, with the inner kbd p173 elements representing each individual step of the input, and the
samp p172 elements inside them indicating that the steps are input based on something being displayed by
the system, in this case menu labels:
173
To make George eat an apple, select
File Eat Apple...
Such precision isn't necessary; the following is equally fine:
To make George eat an apple, select File | Eat Apple...
4.6.14 The sub and sup elements
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which these elements may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Use HTMLElement p81 .
The sup p174 element represents p638 a superscript and the sub p174 element represents p638 a subscript.
These elements must be used only to mark up typographical conventions with specific meanings, not for
typographical presentation for presentation's sake. For example, it would be inappropriate for the sub p174 and
sup p174 elements to be used in the name of the LaTeX document preparation system. In general, authors should
use these elements only if the absence of those elements would change the meaning of the content.
In certain languages, superscripts are part of the typographical conventions for some abbreviations.
The most beautiful women are
Mlle GwendolineMme Denise
The sub p174 element can be used inside a var p172 element, for variables that have subscripts.
Here, the sub p174 element is used to represents the subscript that identifies the variable in a family of
variables:
The coordinate of the i th point is
(xi , yi ).
For example, the 10th point has coordinate
(x10 , y10 ).
Mathematical expressions often use subscripts and superscripts. Authors are encouraged to use MathML for
marking up mathematics, but authors may opt to use sub p174 and sup p174 if detailed mathematical markup is not
desired. [MATHML] p702
E =m c 2
f(x , n ) = log4 x n The Felis silvestris catus is cute.
The term prose content is defined above.
There is a certain je ne sais quoi in the air.
In the following example, a dream sequence is marked up using i p174 elements.
Raymond tried to sleep.
The ship sailed away on Thursday , he
dreamt. The ship had many people aboard, including a beautiful
princess called Carey. He watched her, day-in, day-out, hoping she
would notice him, but she never did.
Finally one night he picked up the courage to speak with
her—
Raymond woke with a start as the fire alarm rang out.
Authors are encouraged to use the class p86 attribute on the i p174 element to identify why the element is being
used, so that if the style of a particular use (e.g. dream sequences as opposed to taxonomic terms) is to be
changed at a later date, the author doesn't have to go through the entire document (or series of related
documents) annotating each use. Similarly, authors are encouraged to consider whether other elements might be
more applicable than the i p174 element, for instance the em p162 element for marking up stress emphasis, or the
dfn p167 element to mark up the defining instance of a term.
Note: Style sheets can be used to format i p174 elements, just like any other element can be
restyled. Thus, it is not the case that content in i p174 elements will necessarily be italicized.
4.6.16 The b element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The b p175 element represents p638 a span of text to be stylistically offset from the normal prose without conveying
any extra importance, such as key words in a document abstract, product names in a review, or other spans of
text whose typical typographic presentation is boldened.
The following example shows a use of the b p175 element to highlight key words without marking them up as
important:
The frobonitor and barbinator components are fried.
In the following example, objects in a text adventure are highlighted as being special by use of the b p175
element.
You enter a small room. Your sword glows
brighter. A rat scurries past the corner wall.
175
Another case where the b p175 element is appropriate is in marking up the lede (or lead) sentence or
paragraph. The following example shows how a BBC article about kittens adopting a rabbit as their own
could be marked up:
Kittens 'adopted' by pet rabbit
Six abandoned kittens have found an
unexpected new mother figure — a pet rabbit.
Veterinary nurse Melanie Humble took the three-week-old
kittens to her Aberdeen home.
[...]
As with the i p174 element, authors are encouraged to use the class p86 attribute on the b p175 element to identify
why the element is being used, so that if the style of a particular use is to be changed at a later date, the author
doesn't have to go through annotating each use.
The b p175 element should be used as a last resort when no other element is more appropriate. In particular,
headings should use the h1 p139 to h6 p139 elements, stress emphasis should use the em p162 element, importance
should be denoted with the strong p163 element, and text marked or highlighted should use the mark p176 element.
The following would be incorrect usage:
WARNING! Do not frob the barbinator!
In the previous example, the correct element to use would have been strong p163 , not b p175 .
Note: Style sheets can be used to format b p175 elements, just like any other element can be
restyled. Thus, it is not the case that content in b p175 elements will necessarily be boldened.
4.6.17 The mark element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The mark p176 element represents p638 a run of text in one document marked or highlighted for reference purposes,
due to its relevance in another context. When used in a quotation or other block of text referred to from the prose,
it indicates a highlight that was not originally present but which has been added to bring the reader's attention to
a part of the text that might not have been considered important by the original author when the block was
originally written, but which is now under previously unexpected scrutiny. When used in the main prose of a
document, it indicates a part of the document that has been highlighted due to its likely relevance to the user's
current activity.
This example shows how the mark p176 element can be used to bring attention to a particular part of a
quotation:
Consider the following quote:
Look around and you will find, no-one's really
colour blind.
As we can tell from the spelling of the word,
the person writing this quote is clearly not American.
Another example of the mark p176 element is highlighting parts of a document that are matching some search
string. If someone looked at a document, and the server knew that the user was searching for the word
"kitten", then the server might return the document with one paragraph modified as follows:
176
I also have some kitten s who are visiting me
these days. They're really cute. I think they like my garden! Maybe I
should adopt a kitten .
In the following snippet, a paragraph of text refers to a specific part of a code fragment.
The highlighted part below is where the error lies:
var i: Integer;
begin
i := 1.1 ;
end.
She knew
Did you notice the subtle joke in the joke on panel 4?
I didn't want to believe. Of course
on some level I realized it was a known-plaintext attack. But I
couldn't admit it until I saw for myself.
(Emphasis mine.) I thought that was great. It's so pedantic, yet it
explains everything neatly.
Note, incidentally, the distinction between the em p162 element in this example, which is part of the original
text being quoted, and the mark p176 element, which is highlighting a part for comment.
The following example shows the difference between denoting the importance of a span of text (strong p163 )
as opposed to denoting the relevance of a span of text (mark p176 ). It is an extract from a textbook, where the
extract has had the parts relevant to the exam highlighted. The safety warnings, important though they
may be, are apparently not relevant to the exam.
Wormhole Physics Introduction
A wormhole in normal conditions can be held open for a
maximum of just under 39 minutes. Conditions that can increase
the time include a powerful energy source coupled to one or both of
the gates connecting the wormhole, and a large gravity well (such as a
black hole).
Momentum is preserved across the wormhole. Electromagnetic
radiation can travel in both directions through a wormhole,
but matter cannot.
When a wormhole is created, a vortex normally forms.
Warning: The vortex caused by the wormhole opening will
annihilate anything in its path. Vortexes can be avoided when
using sufficiently advanced dialing technology.
An obstruction in a gate will prevent it from accepting a
wormhole connection.
4.6.18 The ruby element
177
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
One or more groups of: phrasing content p91 followed either by a single rt p179 element, or an rp p179
element, an rt p179 element, and another rp p179 element.
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The ruby p177 element allows one or more spans of phrasing content to be marked with ruby annotations. Ruby
annotations are short runs of text presented alongside base text, primarily used in East Asian typography as a
guide for pronunciation or to include other annotations. In Japanese, this form of typography is also known as
furigana.
A ruby p177 element represents p638 the spans of phrasing content it contains, ignoring all the child rt p179 and rp p179
elements and their descendants. Those spans of phrasing content have associated annotations created using the
rt p179 element.
In this example, each ideograph in the Japanese text 漢字 is annotated with its reading in hiragana.
...
漢 かん
字 じ
...
This might be rendered as:
In this example, each ideograph in the traditional Chinese text 漢字 is annotated with its bopomofo reading.
漢 ㄏㄢˋ
字 ㄗˋ
This might be rendered as:
In this example, each ideograph in the simplified Chinese text 汉字 is annotated with its pinyin reading.
...
汉 hàn
字 zì
178
...
This might be rendered as:
4.6.19 The rt element
Categories
None.
Contexts in which this element may be used:
As a child of a ruby p177 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The rt p179 element marks the ruby text component of a ruby annotation.
An rt p179 element that is a child of a ruby p177 element represents p638 an annotation (given by its children) for the
zero or more nodes of phrasing content that immediately precedes it in the ruby p177 element, ignoring rp p179
elements.
An rt p179 element that is not a child of a ruby p177 element represents the same thing as its children.
4.6.20 The rp element
Categories
None.
Contexts in which this element may be used:
As a child of a ruby p177 element, either immediately before or immediately after an rt p179 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The rp p179 element can be used to provide parentheses around a ruby text component of a ruby annotation, to be
shown by user agents that don't support ruby annotations.
An rp p179 element that is a child of a ruby p177 element represents p638 nothing and its contents must be ignored. An
rp p179 element whose parent element is not a ruby p177 element represents p638 its children.
The example above, in which each ideograph in the text 漢字 is annotated with its kanji reading, could be
expanded to use rp p179 so that in legacy user agents the readings are in parentheses:
...
漢 ( かん )
字 ( じ )
...
179
In conforming user agents the rendering would be as above, but in user agents that do not support ruby, the
rendering would be:
... 漢 (かん) 字 (じ) ...
4.6.21 The bdo element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
Also, the dir p86 global attribute has special semantics on this element.
DOM interface:
Uses HTMLElement p81 .
The bdo p180 element represents p638 explicit text directionality formatting control for its children. It allows authors to
override the Unicode bidirectional algorithm by explicitly specifying a direction override. [BIDI] p700
Authors must specify the dir p86 attribute on this element, with the value ltr to specify a left-to-right override and
with the value rtl to specify a right-to-left override.
If the element has the dir p86 attribute set to the exact value ltr, then for the purposes of the bidi algorithm, the
user agent must act as if there was a U+202D LEFT-TO-RIGHT OVERRIDE character at the start of the element, and
a U+202C POP DIRECTIONAL FORMATTING at the end of the element.
If the element has the dir p86 attribute set to the exact value rtl, then for the purposes of the bidi algorithm, the
user agent must act as if there was a U+202E RIGHT-TO-LEFT OVERRIDE character at the start of the element, and
a U+202C POP DIRECTIONAL FORMATTING at the end of the element.
The requirements on handling the bdo p180 element for the bidi algorithm may be implemented indirectly through
the style layer. For example, an HTML+CSS user agent should implement these requirements by implementing the
CSS 'unicode-bidi' property. [CSS] p700
4.6.22 The span element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
interface HTMLSpanElement : HTMLElement {};
The span p180 element doesn't mean anything on its own, but can be useful when used together with other
attributes, e.g. class p86 , lang p85 , or dir p86 . It represents p638 its children.
In this example, a code fragment is marked up using span p180 elements and class p86 attributes so that its
keywords and identifiers can be color-coded from CSS:
for (j = 0; j < 256; j ++) {
i_t3 = (i_t3 & 0x1ffff) |
(j << 17);
180
i_t6 = (((((((i_t3 >> 3) ^
i_t3 ) >> 1) ^ i_t3 ) >> 8) ^
i_t3 ) >> 5) & 0xff;
if (i_t6 == i_t1 )
break ;
}P. Sherman
br p181 elements must not be used for separating thematic groups in a paragraph.
The following examples are non-conforming, as they abuse the br p181 element:
34 comments. Add a comment.
Name: Address:
Here are alternatives to the above, which are correct:
34 comments.
Add a comment.
Name:
Address:
If a paragraph p93 consists of nothing but a single br p181 element, it represents a placeholder blank line (e.g. as in a
template). Such blank lines must not be used for presentation purposes.
Any content inside br p181 elements must not be considered part of the surrounding text.
A br p181 element does not separate paragraphs for the purposes of the Unicode bidirectional algorithm. [BIDI] p700
4.6.24 The wbr element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Empty.
181
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The wbr p181 element represents p638 a line break opportunity.
In the following example, someone is quoted as saying something which, for effect, is written as one long
word. However, to ensure that the text can be wrapped in a readable fashion, the individual words in the
quote are separated using a wbr p181 element.
So then he pointed at the tiger and screamed
"thereisnowayyouareevergoingtocatchme"!
Any content inside wbr p181 elements must not be considered part of the surrounding text.
4.6.25 Usage summary
This section is non-normative.
Element
p160
Purpose
Example
Hyperlinks
Visit my drinks page.
em p162
Stress emphasis
I must say I adore lemonade.
strong p163
Importance
This tea is very hot .
small p164
Side comments
These grapes are made into wine. Alcohol is addictive.
cite p165
Titles of works
The case Hugo v. Danielle is relevant here.
q p166
Quotations
The judge said You can drink water from the fish tank but advised against
it.
dfn p167
Defining instance
The term organic food refers to food produced without synthetic
chemicals.
abbr p167
Abbreviations
Organic food in Ireland is certified by the IOFGA .
time p168
Date and/or time
Published 2009-10-21 .
code p171
Computer code
The fruitdb program can be used for tracking fruit production.
a
p172
Variables
If there are n fruit in the bowl, at least n ÷2 will be ripe.
samp p172
Computer output
The computer said Unknown error -3 .
kbd p173
User input
Hit F1 to continue.
sub p174
Subscripts
Water is H2 O.
sup p174
Superscripts
The Hydrogen in heavy water is usually 2 H.
i p174
Alternative voice
Lemonade consists primarily of Citrus limon .
Keywords
Take a lemon and squeeze it with a juicer .
Highlight
Elderflower cordial, with one part cordial to ten part s
water, stands apart from the rest.
ruby p177 ,
rt p179 , rp p179
Ruby annotations
OJ (Orange Juice)
bdo p180
Text directionality
formatting
The proposal is to write English, but in reverse order. "Juice" would become "Juice "
span p180
Other
In French we call it sirop de sureau .
br p181
Line break
Simply Orange Juice Companyorangejuice.com
var
b
p175
mark
p176
4.7 Edits
The ins p182 and del p183 elements represent edits to the document.
4.7.1 The ins element
Categories
Flow content p91 .
When the element only contains phrasing content p91 : phrasing content p91 .
182
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Transparent p93 .
Content attributes:
Global attributes p82
cite p184
datetime p184
DOM interface:
Uses the HTMLModElement p184 interface.
The ins p182 element represents p638 an addition to the document.
The following represents the addition of a single paragraph:
As does this, because everything in the aside p137 element here counts as phrasing content p91 and therefore
there is just one paragraph p93 :
Apples are tasty .
So are pears.
ins p182 elements should not cross implied paragraph p93 boundaries.
The following example represents the addition of two paragraphs, the second of which was inserted in two
parts. The first ins p182 element in this example thus crosses a paragraph boundary, which is considered
poor form.
I like fruit.
Apples are tasty .
So are pears.
Here is a better way of marking this up. It uses more elements, but none of the elements cross implied
paragraph boundaries.
I like fruit.
Apples are tasty .
So are pears.
4.7.2 The del element
183
Categories
Flow content p91 .
When the element only contains phrasing content p91 : phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Transparent p93 .
Content attributes:
Global attributes p82
cite p184
datetime p184
DOM interface:
Uses the HTMLModElement p184 interface.
The del p183 element represents p638 a removal from the document.
del p183 elements should not cross implied paragraph p93 boundaries.
The following shows a "to do" list where items that have been done are crossed-off with the date and time
of their completion.
To Do
Empty the dishwasher
Watch Walter Lewin's lecturesDownload more tracksBuy a printer
4.7.3 Attributes common to ins p182 and del p183 elements
The cite attribute may be used to specify the address of a document that explains the change. When that
document is long, for instance the minutes of a meeting, authors are encouraged to include a fragment identifier
pointing to the specific part of that document that discusses the change.
If the cite p184 attribute is present, it must be a valid URL p51 that explains the change. To obtain the corresponding
citation link, the value of the attribute must be resolved p51 relative to the element. User agents should allow users
to follow such citation links.
The datetime attribute may be used to specify the time and date of the change.
If present, the datetime p184 attribute must be a valid global date and time string p44 value.
User agents must parse the datetime p184 attribute according to the parse a global date and time string p44
algorithm. If that doesn't return a time, then the modification has no associated timestamp (the value is nonconforming; it is not a valid global date and time string p44 ). Otherwise, the modification is marked as having been
made at the given datetime. User agents should use the associated time-zone offset information to determine
which time zone to present the given datetime in.
The ins p182 and del p183 elements must implement the HTMLModElement p184 interface:
interface HTMLModElement : HTMLElement {
attribute DOMString cite;
attribute DOMString dateTime;
};
The cite IDL attribute must reflect p57 the element's cite p184 content attribute. The dateTime IDL attribute must
reflect p57 the element's datetime p184 content attribute.
4.7.4 Edits and paragraphs
This section is non-normative.
184
Since the ins p182 and del p183 elements do not affect paragraphing p93 , it is possible, in some cases where
paragraphs are implied p93 (without explicit p p148 elements), for an ins p182 or del p183 element to span both an entire
paragraph or other non-phrasing content p91 elements and part of another paragraph. For example:
This is a paragraph that was inserted.
This is another paragraph whose first sentence was inserted
at the same time as the paragraph above.
This is a second sentence, which was there all along.
By only wrapping some paragraphs in p p148 elements, one can even get the end of one paragraph, a whole second
paragraph, and the start of a third paragraph to be covered by the same ins p182 or del p183 element (though this is
very confusing, and not considered good practice):
This is the first paragraph. This sentence was
inserted.
This second paragraph was inserted.
This sentence was inserted too. This is the
third paragraph in this example.
However, due to the way implied paragraphs p93 are defined, it is not possible to mark up the end of one paragraph
and the start of the very next one using the same ins p182 or del p183 element. You instead have to use one (or two)
p p148 element(s) and two ins p182 or del p183 elements, as for example:
This is the first paragraph. This sentence was
deleted.
This sentence was deleted too. That
sentence needed a separate <del> element.
Partly because of the confusion described above, authors are strongly encouraged to always mark up all
paragraphs with the p p148 element, instead of having ins p182 or del p183 elements that cross implied paragraphs p93
boundaries.
4.7.5 Edits and lists
This section is non-normative.
The content models of the ol p152 and ul p153 elements do not allow ins p182 and del p183 elements as children. Lists
always represent all their items, including items that would otherwise have been marked as deleted.
To indicate that an item is inserted or deleted, an ins p182 or del p183 element can be wrapped around the contents
of the li p154 element. To indicate that an item has been replaced by another, a single li p154 element can have one
or more del p183 elements followed by one or more ins p182 elements.
In the following example, a list that started empty had items added and removed from it over time. The bits
in the example that have been emphasized show the parts that are the "current" state of the list. The list
item numbers don't take into account the edits, though.
Stop-ship bugs
Bug 225:
Rain detector doesn't work in snow Bug 228:
Water buffer overflows in April Bug 230:
Water heater doesn't use renewable fuels Bug 232:
Carbon dioxide emissions detected after startup
In the following example, a list that started with just fruit was replaced by a list with just colors.
185
List of fruitscolors
LimeGreen AppleOrange
PearTeal LemonYellow Olive
Purple
4.8 Embedded content
4.8.1 The img element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
If the element has a usemap p268 attribute: Interactive content p92 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
Empty.
Content attributes:
Global attributes p82
alt p186
src p186
usemap p268
ismap p189
width p271
height p271
DOM interface:
[NamedConstructor=Image(),
NamedConstructor=Image(in unsigned long width),
NamedConstructor=Image(in unsigned long width, in unsigned long height)]
interface HTMLImageElement : HTMLElement {
attribute DOMString alt;
attribute DOMString src;
attribute DOMString useMap;
attribute boolean isMap;
attribute unsigned long width;
attribute unsigned long height;
readonly attribute unsigned long naturalWidth;
readonly attribute unsigned long naturalHeight;
readonly attribute boolean complete;
};
An img p186 element represents an image.
The image given by the src attribute is the embedded content, and the value of the alt attribute is the img p186
element's fallback content p92 .
The src p186 attribute must be present, and must contain a valid non-empty URL p51 referencing a non-interactive,
optionally animated, image resource that is neither paged nor scripted.
Note: Images can thus be static bitmaps (e.g. PNGs, GIFs, JPEGs), single-page vector
documents (single-page PDFs, XML files with an SVG root element), animated bitmaps
(APNGs, animated GIFs), animated vector graphics (XML files with an SVG root element that
use declarative SMIL animation), and so forth. However, this also precludes SVG files with
script, multipage PDF files, interactive MNG files, HTML documents, plain text documents, and
so forth.
186
The requirements on the alt p186 attribute's value are described in the next section p191 .
The img p186 must not be used as a layout tool. In particular, img p186 elements should not be used to display
transparent images, as they rarely convey meaning and rarely add anything useful to the document.
Unless the user agent cannot support images, or its support for images has been disabled, or the user agent only
fetches elements on demand, then, when an img p186 is created with a src p186 attribute, and whenever the src p186
attribute is set subsequently, the user agent must run the following steps:
1.
If the element's src p186 attribute's value is the empty string, then queue a task p490 to fire a simple
event p496 named error at the img p186 element, and abort these steps.
2.
Otherwise, resolve p51 the value of that attribute, relative to the element, and if that is successful must
then fetch p55 that resource.
Fetching the image must delay the load event p619 of the element's document until the task p489 that is
queued p490 by the networking task source p491 once the resource has been fetched p55 (defined below p187 )
has been run.
⚠Warning! This, unfortunately, can be used to perform a rudimentary port scan of the user's
local network (especially in conjunction with scripting, though scripting isn't actually
necessary to carry out such an attack). User agents may implement cross-origin p449 access
control policies that mitigate this attack.
If the image is in a supported image type and its dimensions are known, then the image is said to be available
(this affects exactly what the element represents, as defined below). This can be true even before the image is
completely downloaded, if the user agent supports incremental rendering of images; in such cases, each task p489
that is queued p490 by the networking task source p491 while the image is being fetched p55 must update the
presentation of the image appropriately. It can also stop being true, e.g. if the user agent finds, after obtaining the
image's dimensions, that the image data is actually fatally corrupted.
If the image was not fetched (e.g. because the UA's image support is disabled, or because the src p186 attribute's
value is the empty string, or if the conditions in the previous paragraph are not met, then the image is not
available p187 .
Whether the image is fetched successfully or not (e.g. whether the response code was a 2xx code or
equivalent p56 ) must be ignored when determining the image's type and whether it is a valid image.
Note: This allows servers to return images with error responses, and have them displayed.
The user agents should apply the image sniffing rules p57 to determine the type of the image, with the image's
associated Content-Type headers p57 giving the official type. If these rules are not applied, then the type of the
image must be the type given by the image's associated Content-Type headers p57 .
User agents must not support non-image resources with the img p186 element (e.g. XML files whose root element is
an HTML element). User agents must not run executable code (e.g. scripts) embedded in the image resource. User
agents must only display the first page of a multipage resource (e.g. a PDF file). User agents must not allow the
resource to act in an interactive fashion, but should honor any animation in the resource.
This specification does not specify which image types are to be supported.
The task p489 that is queued p490 by the networking task source p491 once the resource has been fetched p55 , must act
as appropriate given the following alternatives:
p187
↪ If the download was successful and the image is available
Queue a task p490 to fire a simple event p496 named load at the img p186 element (this happens after
complete p189 starts returning true).
↪ Otherwise (the fetching process failed without a response from the remote server, or completed
but the image is not a supported image)
Queue a task p490 to fire a simple event p496 named error on the img p186 element.
The task source p490 for these tasks p489 is the DOM manipulation task source p491 .
What an img p186 element represents depends on the src p186 attribute and the alt p186 attribute.
p186
attribute is set and the alt p186 attribute is set to the empty string
↪ If the src
The image is either decorative or supplemental to the rest of the content, redundant with some other
information in the document.
187
If the image is available p187 and the user agent is configured to display that image, then the element
represents p638 the image specified by the src p186 attribute.
Otherwise, the element represents p638 nothing, and may be omitted completely from the rendering. User
agents may provide the user with a notification that an image is present but has been omitted from the
rendering.
p186
attribute is set and the alt p186 attribute is set to a value that isn't empty
↪ If the src
The image is a key part of the content; the alt p186 attribute gives a textual equivalent or replacement for
the image.
If the image is available p187 and the user agent is configured to display that image, then the element
represents p638 the image specified by the src p186 attribute.
Otherwise, the element represents p638 the text given by the alt p186 attribute. User agents may provide
the user with a notification that an image is present but has been omitted from the rendering.
p186
attribute is set and the alt p186 attribute is not
↪ If the src
The image might be a key part of the content, and there is no textual equivalent of the image available.
Note: In a conforming document, the absence of the alt p186 attribute indicates that
the image is a key part of the content but that a textual replacement for the image
was not available when the image was generated.
If the image is available p187 , the element represents p638 the image specified by the src p186 attribute.
If the image is not available p187 or if the user agent is not configured to display the image, then the user
agent should display some sort of indicator that there is an image that is not being rendered, and may, if
requested by the user, or if so configured, or when required to provide contextual information in
response to navigation, provide caption information for the image, derived as follows:
1.
If the image has a title p84 attribute whose value is not the empty string, then the value of
that attribute is the caption information; abort these steps.
2.
If the image is the child of a figure p158 element that has a child figcaption p159 element, then
the contents of the first such figcaption p159 element are the caption information; abort these
steps.
3.
Run the algorithm to create the outline p145 for the document.
4.
If the img p186 element did not end up associated with a heading in the outline, or if there are
any other images that are lacking an alt p186 attribute and that are associated with the same
heading in the outline as the img p186 element in question, then there is no caption information;
abort these steps.
5.
The caption information is the heading with which the image is associated according to the
outline.
p186
attribute is not set and either the alt p186 attribute is set to the empty string or the
↪ If the src
alt p186 attribute is not set at all
The element represents p638 nothing.
↪ Otherwise
The element represents p638 the text given by the alt p186 attribute.
The alt p186 attribute does not represent advisory information. User agents must not present the contents of the
alt p186 attribute in the same way as content of the title p84 attribute.
User agents may always provide the user with the option to display any image, or to prevent any image from
being displayed. User agents may also apply heuristics to help the user make use of the image when the user is
unable to see it, e.g. due to a visual disability or because they are using a text terminal with no graphics
capabilities. Such heuristics could include, for instance, optical character recognition (OCR) of text found within
the image.
⚠Warning! While user agents are encouraged to repair cases of missing alt p186 attributes, authors
must not rely on such behavior. Requirements for providing text to act as an alternative for
images p191 are described in detail below.
The contents of img p186 elements, if any, are ignored for the purposes of rendering.
The usemap p268 attribute, if present, can indicate that the image has an associated image map p268 .
188
The ismap attribute, when used on an element that is a descendant of an a p160 element with an href p383 attribute,
indicates by its presence that the element provides access to a server-side image map. This affects how events
are handled on the corresponding a p160 element.
The ismap p189 attribute is a boolean attribute p34 . The attribute must not be specified on an element that does not
have an ancestor a p160 element with an href p383 attribute.
The img p186 element supports dimension attributes p271 .
The IDL attributes alt, src, useMap, and isMap each must reflect p57 the respective content attributes of the same
name.
This box is non-normative. Implementation requirements are given below this box.
image . width
p189
[ = value ]
image . height p189 [ = value ]
These attributes return the actual rendered dimensions of the image, or zero if the dimensions are not
known.
They can be set, to change the corresponding content attributes.
image . naturalWidth p189
image . naturalHeight p189
These attributes return the intrinsic dimensions of the image, or zero if the dimensions are not known.
image . complete p189
Returns true if the image has been downloaded, decoded, and found to be valid; otherwise, returns
false.
image = new Image p189 ( [ width [, height ] ] )
Returns a new img p186 element, with the width p271 and height p271 attributes set to the values passed in
the relevant arguments, if applicable.
The IDL attributes width and height must return the rendered width and height of the image, in CSS pixels, if the
image is being rendered p638 , and is being rendered to a visual medium; or else the intrinsic width and height of the
image, in CSS pixels, if the image is available p187 but not being rendered to a visual medium; or else 0, if the
image is not available p187 . [CSS] p700
On setting, they must act as if they reflected p57 the respective content attributes of the same name.
The IDL attributes naturalWidth and naturalHeight must return the intrinsic width and height of the image, in
CSS pixels, if the image is available p187 , or else 0. [CSS] p700
The IDL attribute complete must return true if the user agent has fetched the image specified in the src p186
attribute, and it is in a supported image type (i.e. it was decoded without fatal errors), even if the final task p489
queued by the networking task source p491 for the fetching p55 of the image resource has not yet been processed.
Otherwise, the attribute must return false.
Note: The value of complete p189 can thus change while a script p487 is executing.
Three constructors are provided for creating HTMLImageElement p186 objects (in addition to the factory methods
from DOM Core such as createElement()): Image(), Image(width), and Image(width, height). When invoked
as constructors, these must return a new HTMLImageElement p186 object (a new img p186 element). If the width
argument is present, the new object's width p271 content attribute must be set to width. If the height argument is
also present, the new object's height p271 content attribute must be set to height. The element's document must
be the active document p439 of the browsing context p439 of the Window p443 object on which the interface object of
the invoked constructor is found.
A single image can have different appropriate alternative text depending on the context.
In each of the following cases, the same image is used, yet the alt p186 text is different each time. The image
is the coat of arms of the Carouge municipality in the canton Geneva in Switzerland.
Here it is used as a supplementary icon:
I lived in
Here it is used as an icon representing the town:
Home town:
189
Here it is used as part of a text on the town:
Carouge has a coat of arms.
It is used as decoration all over the town.
Here it is used as a way to support a similar text where the description is given as well as, instead of as an
alternative to, the image:
Carouge has a coat of arms.
The coat of arms depicts a lion, sitting in front of a tree.
It is used as decoration all over the town.
Here it is used as part of a story:
He picked up the folder and a piece of paper fell out.
He stared at the folder. S! The answer he had been looking for all
this time was simply the letter S! How had he not seen that before? It all
came together now. The phone call where Hector had referred to a lion's tail,
the time Marco had stuck his tongue out...
Here it is not known at the time of publication what the image will be, only that it will be a coat of arms of
some kind, and thus no replacement text can be provided, and instead only a brief caption for the image is
provided, in the title p84 attribute:
The last user to have uploaded a coat of arms uploaded this one:
Ideally, the author would find a way to provide real replacement text even in this case, e.g. by asking the
previous user. Not providing replacement text makes the document more difficult to use for people who are
unable to view images, e.g. blind users, or users or very low-bandwidth connections or who pay by the byte,
or users who are forced to use a text-only Web browser.
Here are some more examples showing the same picture used in different contexts, with different
appropriate alternate texts each time.
My cats
Fluffy
Fluffy is my favorite.
She's just too cute.
Miles
My other cat, Miles just eats and sleeps.
Photography
Shooting moving targets indoors
The trick here is to know how to anticipate; to know at what speed and
what distance the subject will pass by.
Nature by night
To achieve this, you'll need either an extremely sensitive film, or
immense flash lights.
About me
My pets
I've got a cat named Fluffy and a dog named Miles.
My dog Miles and I like go on long walks together.
music
After our walks, having emptied my mind, I like listening to Bach.
Fluffy and the Yarn
Fluffy was a cat who liked to play with yarn. He also liked to jump.
190
He would play in the morning, he would play in the evening.
4.8.1.1 Requirements for providing text to act as an alternative for images
Except where otherwise specified, the alt p186 attribute must be specified and its value must not be empty; the
value must be an appropriate replacement for the image. The specific requirements for the alt p186 attribute
depend on what the image is intended to represent, as described in the following sections.
4.8.1.1.1 A link or button containing nothing but the image
When an a p160 element that is a hyperlink p383 , or a button p332 element, has no textual content but contains one or
more images, the alt p186 attributes must contain text that together convey the purpose of the link or button.
In this example, a user is asked to pick his preferred color from a list of three. Each color is given by an
image, but for users who have configured their user agent not to display images, the color names are used
instead:
Pick your color
In this example, each button has a set of images to indicate the kind of color output desired by the user.
The first image is used in each case to give the alternative text.
In the common case, the data handled by the tokenization stage
comes from the network, but it can also come from script.
Here's another example, showing a good solution and a bad solution to the problem of including an image in
a description.
First, here's the good solution. This sample shows how the alternative text should just be what you would
have put in the prose if the image had never existed.
You are standing in an open field west of a house.
Second, here's the bad solution. In this incorrect way of doing things, the alternative text is simply a
description of the image, instead of a textual replacement for the image. It's bad because when the image
isn't shown, the text doesn't flow as well as in the first example.
You are standing in an open field west of a house.
Text such as "Photo of white house with boarded door" would be equally bad alternative text (though it
could be suitable for the title p84 attribute or in the figcaption p159 element of a figure p158 with this
image).
4.8.1.1.3 A short phrase or label with an alternative graphical representation: icons, logos
A document can contain information in iconic form. The icon is intended to help users of visual browsers to
recognize features at a glance.
In some cases, the icon is supplemental to a text label conveying the same meaning. In those cases, the alt p186
attribute must be present but must be empty.
Here the icons are next to text that conveys the same meaning, so they have an empty alt p186 attribute:
In other cases, the icon has no text next to it describing what it means; the icon is supposed to be selfexplanatory. In those cases, an equivalent textual label must be given in the alt p186 attribute.
Here, posts on a news site are labeled with an icon indicating their topic.
Ratatouille wins Best Movie of the Year award
Pixar has won yet another Best Movie of the Year award,
making this its 8th win in the last 12 years.
Latest TWiT episode is online
The latest TWiT episode has been posted, in which we hear
several tech news stories as well as learning much more about the
iPhone. This week, the panelists compare how reflective their
iPhones' Apple logos are.
192
Many pages include logos, insignia, flags, or emblems, which stand for a particular entity such as a company,
organization, project, band, software package, country, or some such.
If the logo is being used to represent the entity, e.g. as a page heading, the alt p186 attribute must contain the
name of the entity being represented by the logo. The alt p186 attribute must not contain text like the word "logo",
as it is not the fact that it is a logo that is being conveyed, it's the entity itself.
If the logo is being used next to the name of the entity that it represents, then the logo is supplemental, and its
alt p186 attribute must instead be empty.
If the logo is merely used as decorative material (as branding, or, for example, as a side image in an article that
mentions the entity to which the logo belongs), then the entry below on purely decorative images applies. If the
logo is actually being discussed, then it is being used as a phrase or paragraph (the description of the logo) with
an alternative graphical representation (the logo itself), and the first entry above applies.
In the following snippets, all four of the above cases are present. First, we see a logo used to represent a
company:
News
We have recently been looking at buying the
In this third snippet, we have a logo being used in an aside, as part of the larger article discussing the
acquisition:
The ΑΒΓ company has had a good quarter, and our
pie chart studies of their accounts suggest a much bigger blue slice
than its green and orange slices, which is always a good sign.
Finally, we have an opinion piece talking about a logo, and the logo is therefore described in detail in the
alternative text.
Consider for a moment their logo:
How unoriginal can you get? I mean, oooooh, a question mark, how
revolutionary , how utterly ground-breaking , I'm
sure everyone will rush to adopt those specifications now! They could
at least have tried for some sort of, I don't know, sequence of
rounded squares with varying shades of green and bold white outlines,
at least that would look good on the cover of a blue book.
This example shows how the alternative text should be written such that if the image isn't available p187 , and
the text is used instead, the text flows seamlessly into the surrounding text, as if the image had never been
there in the first place.
4.8.1.1.4 Text that has been rendered to a graphic for typographical effect
Sometimes, an image just consists of text, and the purpose of the image is not to highlight the actual typographic
effects used to render the text, but just to convey the text itself.
In such cases, the alt p186 attribute must be present but must consist of the same text as written in the image
itself.
Consider a graphic containing the text "Earth Day", but with the letters all decorated with flowers and
plants. If the text is merely being used as a heading, to spice up the page for graphical users, then the
correct alternative text is just the same text "Earth Day", and no mention need be made of the decorations:
The network passes data to the Tokenizer stage, which
passes data to the Tree Construction stage. From there, data goes
to both the DOM and to Script Execution. Script Execution is
linked to the DOM, and, using document.write(), passes data to
the Tokenizer.
In these cases, it would be wrong to include alternative text that consists of just a caption. If a caption is to
be included, then either the title p84 attribute can be used, or the figure p158 and figcaption p159 elements
can be used. In the latter case, the image would in fact be a phrase or paragraph with an alternative
graphical representation, and would thus require alternative text.
The network passes data to the Tokenizer stage, which
passes data to the Tree Construction stage. From there, data goes
to both the DOM and to Script Execution. Script Execution is
linked to the DOM, and, using document.write(), passes data to
the Tokenizer.
The network passes data to the Tokenizer stage, which
passes data to the Tree Construction stage. From there, data goes
to both the DOM and to Script Execution. Script Execution is
linked to the DOM, and, using document.write(), passes data to
the Tokenizer.
Flowchart representation of the parsing model.
The network passes data to the Tokenizer stage, which
passes data to the Tree Construction stage. From there, data goes
to both the DOM and to Script Execution. Script Execution is
linked to the DOM, and, using document.write(), passes data to
the Tokenizer.
A graph that repeats the previous paragraph in graphical form:
According to a study covering several billion pages,
about 62% of documents on the Web in 2007 triggered the Quirks
rendering mode of Web browsers, about 30% triggered the Almost
Standards mode, and about 9% triggered the Standards mode.
4.8.1.1.6 A purely decorative image that doesn't add any information
In general, if an image is decorative but isn't especially page-specific, for example an image that forms part of a
site-wide design scheme, the image should be specified in the site's CSS, not in the markup of the document.
However, a decorative image that isn't discussed by the surrounding text but still has some relevance can be
included in a page using the img p186 element. Such images are decorative, but still form part of the content. In
these cases, the alt p186 attribute must be present but its value must be the empty string.
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Examples where the image is purely decorative despite being relevant would include things like a photo of
the Black Rock City landscape in a blog post about an event at Burning Man, or an image of a painting
inspired by a poem, on a page reciting that poem. The following snippet shows an example of the latter
case (only the first verse is included in this snippet):
The Lady of Shalott
On either side the river lie
4.8.1.1.7 A group of images that form a single larger picture with no links
When a picture has been sliced into smaller image files that are then displayed together to form the complete
picture again, one of the images must have its alt p186 attribute set as per the relevant rules that would be
appropriate for the picture as a whole, and then all the remaining images must have their alt p186 attribute set to
the empty string.
In the following example, a picture representing a company logo for XYZ Corp has been split into two pieces,
the first containing the letters "XYZ" and the second with the word "Corp". The alternative text ("XYZ Corp")
is all in the first image.
Rating:
4.8.1.1.8 A group of images that form a single larger picture with links
Generally, image maps p268 should be used instead of slicing an image for links.
However, if an image is indeed sliced and any of the components of the sliced picture are the sole contents of
links, then one image per link must have alternative text in its alt p186 attribute representing the purpose of the
link.
In the following example, a picture representing the flying spaghetti monster emblem, with each of the left
noodly appendages and the right noodly appendages in different images, so that the user can pick the left
side or the right side in an adventure.
The Church
You come across a flying spaghetti monster. Which side of His
Noodliness do you wish to reach out for?
4.8.1.1.9 A key part of the content
In some cases, the image is a critical part of the content. This could be the case, for instance, on a page that is
part of a photo gallery. The image is the whole point of the page containing it.
How to provide alternative text for an image that is a key part of the content depends on the image's provenance.
The general case
When it is possible for detailed alternative text to be provided, for example if the image is part of a series of
screenshots in a magazine review, or part of a comic strip, or is a photograph in a blog entry about that
photograph, text that can serve as a substitute for the image must be given as the contents of the alt p186
attribute.
A screenshot in a gallery of screenshots for a new OS, with some alternative text:
195
Screenshot of a KDE desktop.
A graph in a financial report:
A black outline of the first of the ten cards
in the Rorschach inkblot test.
Note that the following would be a very bad use of alternative text:
A black outline of the first of the ten cards
in the Rorschach inkblot test.
Including the caption in the alternative text like this isn't useful because it effectively duplicates the
caption for users who don't have images, taunting them twice yet not helping them any more than if
they had only read or heard the caption once.
Another example of an image that defies full description is a fractal, which, by definition, is infinite in
detail.
The following example shows one possible way of providing alternative text for the full view of an
image of the Mandelbrot set.
Bubbles traveled everywhere with us.
It could also be marked up like this:
Bubbles traveled everywhere with us.
In either case, though, it would be better if a detailed description of the important parts of the image
obtained from the user and included on the page.
A blind user's blog in which a photo taken by the user is shown. Initially, the user might not have any
idea what the photo he took shows:
I took a photo
I went out today and took a photo!
A photograph taken blindly from my front porch.
Eventually though, the user might obtain a description of the image from his friends and could then
include alternative text:
I took a photo
I went out today and took a photo!
A photograph taken blindly from my front porch.
Sometimes the entire point of the image is that a textual description is not available, and the user is to
provide the description. For instance, the point of a CAPTCHA image is to see if the user can literally
read the graphic. Here is one way to mark up a CAPTCHA (note the title p84 attribute):
What does this image say?
(If you cannot see the image, you can use an audio test instead.)
197
Another example would be software that displays images and asks for alternative text precisely for the
purpose of then writing a page with correct alternative text. Such a page could have a table of images,
like this:
Notice that even in this example, as much useful information as possible is still included in the
title p84 attribute.
Note: Since some users cannot use images at all (e.g. because they have a very slow
connection, or because they are using a text-only browser, or because they are listening
to the page being read out by a hands-free automobile voice Web browser, or simply
because they are blind), the alt p186 attribute is only allowed to be omitted rather than
being provided with replacement text when no alternative text is available and none can
be made available, as in the above examples. Lack of effort from the part of the author is
not an acceptable reason for omitting the alt p186 attribute.
4.8.1.1.10 An image not intended for the user
Generally authors should avoid using img p186 elements for purposes other than showing images.
If an img p186 element is being used for purposes other than showing an image, e.g. as part of a service to count
page views, then the alt p186 attribute must be the empty string.
In such cases, the width p271 and height p271 attributes should both be set to zero.
4.8.1.1.11 An image in an e-mail or private document intended for a specific person who is known to
be able to view images
This section does not apply to documents that are publicly accessible, or whose target audience is not necessarily
personally known to the author, such as documents on a Web site, e-mails sent to public mailing lists, or software
documentation.
When an image is included in a private communication (such as an HTML e-mail) aimed at a specific person who is
known to be able to view images, the alt p186 attribute may be omitted. However, even in such cases it is strongly
recommended that alternative text be included (as appropriate according to the kind of image involved, as
described in the above entries), so that the e-mail is still usable should the user use a mail client that does not
support images, or should the document be forwarded on to other users whose abilities might not include easily
seeing images.
4.8.1.1.12 General guidelines
The most general rule to consider when writing alternative text is the following: the intent is that replacing
every image with the text of its alt p186 attribute not change the meaning of the page.
So, in general, alternative text can be written by considering what one would have written had one not been able
to include the image.
A corollary to this is that the alt p186 attribute's value should never contain text that could be considered the
image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of
the image; it is not meant to supplement the image. The title p84 attribute can be used for supplemental
information.
Note: One way to think of alternative text is to think about how you would read the page
containing the image to someone over the phone, without mentioning that there is an image
present. Whatever you say instead of the image is typically a good start for writing the
alternative text.
198
4.8.1.1.13 Guidance for markup generators
Markup generators (such as WYSIWYG authoring tools) should, wherever possible, obtain alternative text from
their users. However, it is recognized that in many cases, this will not be possible.
For images that are the sole contents of links, markup generators should examine the link target to determine the
title of the target, or the URL of the target, and use information obtained in this manner as the alternative text.
As a last resort, implementors should either set the alt p186 attribute to the empty string, under the assumption
that the image is a purely decorative image that doesn't add any information but is still specific to the surrounding
content, or omit the alt p186 attribute altogether, under the assumption that the image is a key part of the content.
Markup generators should generally avoid using the image's own file name as the alternative text. Similarly,
markup generators should avoid generating alternative text from any content that will be equally available to
presentation user agents (e.g. Web browsers).
Note: This is because once a page is generated, it will typically not be updated, whereas the
browsers that later read the page can be updated by the user, therefore the browser is likely
to have more up-to-date and finely-tuned heuristics than the markup generator did when
generating the page.
4.8.1.1.14 Guidance for conformance checkers
A conformance checker must report the lack of an alt p186 attribute as an error unless one of the conditions listed
below applies:
•
The title p84 attribute is present and has a non-empty value (as described above p196 ).
•
The img p186 element is in a figure p158 element that contains a figcaption p159 element that contains
content other than inter-element whitespace p89 (as described above p196 ).
•
The img p186 element is part of the only paragraph p93 directly in its section p145 , and is the only img p186
element without an alt p186 attribute in its section, and its section p145 has an associated heading (as
described above p196 ).
•
The conformance checker has been configured to assume that the document is an e-mail or document
intended for a specific person who is known to be able to view images.
•
The document has a meta p112 element with a name p113 attribute whose value is an ASCII caseinsensitive p33 match for the string "generator p114 ". (This case does not represent a case where the
document is conforming, only that the generator could not determine appropriate alternative text —
validators are required to not show an error in this case to discourage markup generators from including
bogus alternative text purely in an attempt to silence validators.)
4.8.2 The iframe element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
Interactive content p92 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
Text that conforms to the requirements given in the prose.
Content attributes:
Global attributes p82
src p200
srcdoc p200
name p202
sandbox p202
seamless p204
width p271
height p271
199
DOM interface:
interface HTMLIFrameElement : HTMLElement {
attribute DOMString src;
attribute DOMString srcdoc;
attribute DOMString name;
[PutForwards=value] readonly attribute DOMSettableTokenList sandbox;
attribute boolean seamless;
attribute DOMString width;
attribute DOMString height;
readonly attribute Document contentDocument;
readonly attribute WindowProxy contentWindow;
};
The iframe p199 element represents p638 a nested browsing context p439 .
The src attribute gives the address of a page that the nested browsing context p439 is to contain. The attribute, if
present, must be a valid non-empty URL p51 .
The srcdoc attribute gives the content of the page that the nested browsing context p439 is to contain. The value of
the attribute in is an iframe srcdoc document.
For iframe p199 elements in HTML documents p71 , the attribute, if present, must have a value using the HTML
syntax p547 that consists of the following syntactic components, in the given order:
1.
Any number of comments p554 and space characters p34 .
2.
Optionally, a DOCTYPE p547 .
3.
Any number of comments p554 and space characters p34 .
4.
The root element, in the form of an html p106 element p548 .
5.
Any number of comments p554 and space characters p34 .
For iframe p199 elements in XML documents p71 , the attribute, if present, must have a value that matches the
production labeled document p31 in the XML specification. [XML] p705
If the src p200 attribute and the srcdoc p200 attribute are both specified together, the srcdoc p200 attribute takes
priority. This allows authors to provide a fallback URL p51 for legacy user agents that do not support the srcdoc p200
attribute.
When an iframe p199 element is first inserted into a document p27 , the user agent must create a nested browsing
context p439 , and then process the iframe attributes p200 for the first time.
Whenever an iframe p199 element with a nested browsing context p439 has its srcdoc p200 attribute set or changed,
the user agent must process the iframe attributes p200 .
Similarly, whenever an iframe p199 element with a nested browsing context p439 but with no srcdoc p200 attribute
specified has its src p200 attribute set or changed, the user agent must process the iframe attributes p200 .
When the user agent is to process the iframe attributes, it must run the first appropriate steps from the
following list:
p200
attribute is specified
↪ If the srcdoc
Navigate p459 the element's browsing context p439 to a resource whose Content-Type p57 is text/html p678 ,
whose URL p51 is about:srcdoc p52 , and whose data consists of the value of the attribute.
p200
attribute is specified but the srcdoc p200 attribute is not
↪ If the src
200
1.
If the value of the src p200 attribute is the empty string, jump to the empty step below.
2.
Resolve p51 the value of the src p200 attribute, relative to the iframe p199 element.
3.
If that is not successful, then jump to the empty step below.
4.
If the resulting absolute URL p52 is an ASCII case-insensitive p33 match for the string
"about:blank p56 ", and the user agent is processing this iframe p199 's attributes for the first
time, then jump to the empty step below. (In cases other than the first time, about:blank p56 is
loaded normally.)
5.
Navigate p459 the element's browsing context p439 to the resulting absolute URL p52 .
Empty: When the steps above require the user agent to jump to the empty step, if the user agent is
processing this iframe p199 's attributes for the first time, then the user agent must queue a task p490 to fire
a simple event p496 named load at the iframe p199 element. (After jumping to this step, the above steps
are not resumed.)
↪ Otherwise
Queue a task p490 to fire a simple event p496 named load at the iframe p199 element.
Any navigation p459 required of the user agent in the process the iframe attributes p200 algorithm must be
completed with the iframe p199 element's document's browsing context p439 as the source browsing context p459 .
Furthermore, if the process the iframe attributes p200 algorithm was invoked for the first time for this element (i.e.
as a result of the element being inserted into a document p27 ), then any navigation p459 required of the user agent in
that algorithm must be completed with replacement enabled p466 .
Note: If, when the element is created, the srcdoc p200 attribute is not set, and the src p200
attribute is either also not set or set but its value cannot be resolved p51 , the browsing context
will remain at the initial about:blank p56 page.
Note: If the user navigates p459 away from this page, the iframe p199 's corresponding
WindowProxy p449 object will proxy new Window p443 objects for new Document p31 objects, but the
src p200 attribute will not change.
Here a blog uses the srcdoc p200 attribute in conjunction with the sandbox p202 and seamless p204 attributes
described below to provide users of user agents that support this feature with an extra layer of protection
from script injection in the blog post comments:
I got my own magazine!
After much effort, I've finally found a publisher, and so now I
have my own magazine! Isn't that awesome?! The first issue will come
out in September, and we have articles about getting food, and about
getting in boxes, it's going to be great!
At 2009-08-21T23:35Z , ch
writes:
At 2009-08-21T23:44Z , cap
writes:
At 2009-08-21T23:58Z , ch
writes:
Notice the way that quotes have to be escaped (otherwise the sandbox p202 attribute would end
prematurely), and the way raw ampersands (e.g. in URLs or in prose) mentioned in the sandboxed content
have to be doubly escaped — once so that the ampersand is preserved when originally parsing the
sandbox p202 attribute, and once more to prevent the ampersand from being misinterpreted when parsing the
sandboxed content.
Note: In the HTML syntax p547 , authors need only remember to use U+0022 QUOTATION MARK
characters (") to wrap the attribute contents and then to escape all U+0022 QUOTATION MARK
(") and U+0026 AMPERSAND (&) characters, and to specify the sandbox p202 attribute, to ensure
safe embedding of content.
Note: Due to restrictions of the XML syntax, in XML a number of other characters need to be
escaped also to ensure correctness.
201
The name attribute, if present, must be a valid browsing context name p442 . The given value is used to name the
nested browsing context p439 . When the browsing context is created, if the attribute is present, the browsing
context name p442 must be set to the value of this attribute; otherwise, the browsing context name p442 must be set
to the empty string.
Whenever the name p202 attribute is set, the nested browsing context p439 's name p442 must be changed to the new
value. If the attribute is removed, the browsing context name p442 must be set to the empty string.
When content loads in an iframe p199 , after any load events are fired within the content itself, the user agent must
queue a task p490 to fire a simple event p496 named load at the iframe p199 element. When content whose URL p51 has
the same origin p451 as the iframe p199 element's Document p31 fails to load (e.g. due to a DNS error, network error, or
if the server returned a 4xx or 5xx status code or equivalent p56 ), then the user agent must queue a task p490 to fire
a simple event p496 named error at the element instead. (This event does not fire for parse errors p554 , script errors,
or any errors for cross-origin resources.)
The task source p490 for these tasks p489 is the DOM manipulation task source p491 .
Note: A load event is also fired at the iframe p199 element when it is created if no other data is
loaded in it.
When there is an active parser p75 in the iframe p199 , and when anything in the iframe p199 is delaying the load
event p619 of the iframe p199 's browsing context p439 's active document p439 , the iframe p199 must delay the load
event p619 of its document.
Note: If, during the handling of the load event, the browsing context p439 in the iframe p199 is
again navigated p459 , that will further delay the load event p619 .
The sandbox attribute, when specified, enables a set of extra restrictions on any content hosted by the iframe p199 .
Its value must be an unordered set of unique space-separated tokens p49 . The allowed values are allow-sameorigin p203 , allow-top-navigation p202 , allow-forms p203 , and allow-scripts p203 . When the attribute is set, the
content is treated as being from a unique origin p449 , forms and scripts are disabled, links are prevented from
targeting other browsing contexts p439 , and plugins are disabled. The allow-same-origin p203 keyword allows the
content to be treated as being from the same origin instead of forcing it into a unique origin, the allow-topnavigation p202 keyword allows the content to navigate p459 its top-level browsing context p439 , and the allowforms p203 and allow-scripts p203 keywords re-enable forms and scripts respectively (though scripts are still
prevented from creating popups).
⚠Warning! Setting both the allow-scripts p203 and allow-same-origin p203 keywords together when the
embedded page has the same origin p451 as the page containing the iframe p199 allows the embedded
page to simply remove the sandbox p202 attribute.
⚠Warning! Sandboxing hostile content is of minimal help if an attacker can convince the user to just
visit the hostile content directly, rather than in the iframe p199 . To limit the damage that can be caused
by hostile HTML content, it should be served using the text/html-sandboxed p679 MIME type.
While the sandbox p202 attribute is specified, the iframe p199 element's nested browsing context p439 must have the
flags given in the following list set. In addition, any browsing contexts nested p439 within an iframe p199 , either
directly or indirectly, must have all the flags set on them as were set on the iframe p199 's Document p31 's browsing
context p439 when the iframe p199 's Document p31 was created.
The sandboxed navigation browsing context flag
This flag prevents content from navigating browsing contexts other than the sandboxed browsing context
itself p459 (or browsing contexts further nested inside it), and the top-level browsing context p439 (which is
protected by the sandboxed top-level navigation browsing context flag p202 defined next).
This flag also prevents content from creating new auxiliary browsing contexts p442 , e.g. using the target p384
attribute or the window.open() p445 method.
The sandboxed top-level navigation browsing context flag, unless the sandbox p202 attribute's value,
when split on spaces p49 , is found to have the allow-top-navigation keyword set
This flag prevents content from navigating their top-level browsing context p459 .
When the allow-top-navigation p202 is set, content can navigate its top-level browsing context p439 , but
other browsing contexts p439 are still protected by the sandboxed navigation browsing context flag p202 defined
above.
The sandboxed plugins browsing context flag
This flag prevents content from instantiating plugins p27 , whether using the embed element p206 , the object
element p211 , the applet element p665 , or through navigation p464 of a nested browsing context p439 .
202
The sandboxed seamless iframes flag
This flag prevents content from using the seamless p204 attribute on descendant iframe p199 elements.
Note: This prevents a page inserted using the allow-same-origin p203 keyword from using a
CSS-selector-based method of probing the DOM of other pages on the same site (in
particular, pages that contain user-sensitive information).
The sandboxed origin browsing context flag, unless the sandbox p202 attribute's value, when split on
spaces p49 , is found to have the allow-same-origin keyword set
This flag forces content into a unique origin p450 , thus preventing it from accessing other content from the
same origin p449 .
This flag also prevents script from reading from or writing to the document.cookie IDL attribute p74 , and
blocks access to localStorage and openDatabase(). [WEBSTORAGE] p704 [WEBSQL] p704
The allow-same-origin p203 attribute is intended for two cases.
First, it can be used to allow content from the same site to be sandboxed to disable
scripting, while still allowing access to the DOM of the sandboxed content.
Second, it can be used to embed content from a third-party site, sandboxed to prevent
that site from opening popup windows, etc, without preventing the embedded page from
communicating back to its originating site, using the database APIs to store data, etc.
The sandboxed forms browsing context flag, unless the sandbox p202 attribute's value, when split on
spaces p49 , is found to have the allow-forms keyword set
This flag blocks form submission p361 .
The sandboxed scripts browsing context flag, unless the sandbox p202 attribute's value, when split on
spaces p49 , is found to have the allow-scripts keyword set
This flag blocks script execution p487 .
The sandboxed automatic features browsing context flag, unless the sandbox p202 attribute's value,
when split on spaces p49 , is found to have the allow-scripts p203 keyword (defined above) set
This flag blocks features that trigger automatically, such as automatically playing a video p231 or
automatically focusing a form control p354 . It is relaxed by the same flag as scripts, because when scripts are
enabled these features are trivially possible anyway, and it would be unfortunate to force authors to use
script to do them when sandboxed rather than allowing them to use the declarative features.
These flags must not be set unless the conditions listed above define them as being set.
⚠Warning! These flags only take effect when the nested browsing context p439 of the iframe p199 is
navigated p459 . Removing then, or removing the entire sandbox p202 attribute, has no effect on an
already-loaded page.
In this example, some completely-unknown, potentially hostile, user-provided HTML content is embedded in
a page. Because it is sandboxed, it is treated by the user agent as being from a unique origin, despite the
content being served from the same site. Thus it is affected by all the normal cross-site restrictions. In
addition, the embedded page has scripting disabled, plugins disabled, forms disabled, and it cannot
navigate any frames or windows other than itself (or any frames or windows it itself embeds).
We're not scared of you! Here is your content, unedited:
Note that cookies are still sent to the server in the getusercontent.cgi request, though they are not
visible in the document.cookie p74 IDL attribute.
⚠Warning! It is important that the server serve the user-provided HTML using the text/htmlsandboxed p679 MIME type so that if the attacker convinces the user to visit that page directly, the
page doesn't run in the context of the site's origin, which would make the user vulnerable to
any attack found in the page.
In this example, a gadget from another site is embedded. The gadget has scripting and forms enabled, and
the origin sandbox restrictions are lifted, allowing the gadget to communicate with its originating server.
The sandbox is still useful, however, as it disables plugins and popups, thus reducing the risk of the user
being exposed to malware and other annoyances.
Suppose a file A contained the following fragment:
203
Suppose that file B contained an iframe also:
Further, suppose that file C contained a link:
Link
For this example, suppose all the files were served as text/html p678 .
Page C in this scenario has all the sandboxing flags set. Scripts are disabled, because the iframe p199 in A
has scripts disabled, and this overrides the allow-scripts p203 keyword set on the iframe p199 in B. Forms are
also disabled, because the inner iframe p199 (in B) does not have the allow-forms p203 keyword set.
Suppose now that a script in A removes all the sandbox p202 attributes in A and B. This would change nothing
immediately. If the user clicked the link in C, loading page D into the iframe p199 in B, page D would now act
as if the iframe p199 in B had the allow-same-origin p203 and allow-forms p203 keywords set, because that
was the state of the nested browsing context p439 in the iframe p199 in A when page B was loaded.
Generally speaking, dynamically removing or changing the sandbox p202 attribute is ill-advised, because it
can make it quite hard to reason about what will be allowed and what will not.
Note: Potentially hostile files can be served from the same server as the file containing the
iframe p199 element by labeling them as text/html-sandboxed p679 instead of text/html p678 . This
ensures that scripts in the files are unable to attack the site (as if they were actually served
from another server), even if the user is tricked into visiting those pages directly, without the
protection of the sandbox p202 attribute.
⚠Warning! If the allow-scripts p203 keyword is set along with allow-same-origin p203 keyword, and the
file is from the same origin p451 as the iframe p199 's Document p31 , then a script in the "sandboxed" iframe
could just reach out, remove the sandbox p202 attribute, and then reload itself, effectively breaking out
of the sandbox altogether.
The seamless attribute is a boolean attribute p34 . When specified, it indicates that the iframe p199 element's
browsing context p439 is to be rendered in a manner that makes it appear to be part of the containing document
(seamlessly included in the parent document). Specifically, when the attribute is set on an iframe p199 element
whose owner Document p31 's browsing context p439 did not have the sandboxed seamless iframes flag p203 set when
that Document p31 was created, and while either the browsing context p439 's active document p439 has the same
origin p451 as the iframe p199 element's document, or the browsing context p439 's active document p439 's address p71
has the same origin p451 as the iframe p199 element's document, the following requirements apply:
•
The user agent must set the seamless browsing context flag to true for that browsing context p439 .
This will cause links to open in the parent browsing context p459 .
•
In a CSS-supporting user agent: the user agent must add all the style sheets that apply to the iframe p199
element to the cascade of the active document p439 of the iframe p199 element's nested browsing
context p439 , at the appropriate cascade levels, before any style sheets specified by the document itself.
•
In a CSS-supporting user agent: the user agent must, for the purpose of CSS property inheritance only,
treat the root element of the active document p439 of the iframe p199 element's nested browsing
context p439 as being a child of the iframe p199 element. (Thus inherited properties on the root element of
the document in the iframe p199 will inherit the computed values of those properties on the iframe p199
element instead of taking their initial values.)
•
In visual media, in a CSS-supporting user agent: the user agent should set the intrinsic width of the
iframe p199 to the width that the element would have if it was a non-replaced block-level element with
'width: auto'.
•
In visual media, in a CSS-supporting user agent: the user agent should set the intrinsic height of the
iframe p199 to the height of the bounding box around the content rendered in the iframe p199 at its current
width (as given in the previous bullet point), as it would be if the scrolling position was such that the top
of the viewport for the content rendered in the iframe p199 was aligned with the origin of that content's
canvas.
•
In visual media, in a CSS-supporting user agent: the user agent must force the height of the initial
containing block of the active document p439 of the nested browsing context p439 of the iframe p199 to zero.
Note: This is intended to get around the otherwise circular dependency of percentage
dimensions that depend on the height of the containing block, thus affecting the
204
height of the document's bounding box, thus affecting the height of the viewport,
thus affecting the size of the initial containing block.
•
In speech media, the user agent should render the nested browsing context p439 without announcing that
it is a separate document.
•
User agents should, in general, act as if the active document p439 of the iframe p199 's nested browsing
context p439 was part of the document that the iframe p199 is in.
For example if the user agent supports listing all the links in a document, links in "seamlessly"
nested documents would be included in that list without being significantly distinguished from
links in the document itself.
If the attribute is not specified, or if the origin p449 conditions listed above are not met, then the user agent should
render the nested browsing context p439 in a manner that is clearly distinguishable as a separate browsing
context p439 , and the seamless browsing context flag p204 must be set to false for that browsing context p439 .
⚠Warning! It is important that user agents recheck the above conditions whenever the active
document p439 of the nested browsing context p439 of the iframe p199 changes, such that the seamless
browsing context flag p204 gets unset if the nested browsing context p439 is navigated p459 to another
origin.
Note: The attribute can be set or removed dynamically, with the rendering updating in
tandem.
In this example, the site's navigation is embedded using a client-side include using an iframe p199 . Any links
in the iframe p199 will, in new user agents, be automatically opened in the iframe p199 's parent browsing
context; for legacy user agents, the site could also include a base p108 element with a target p109 attribute
with the value _parent. Similarly, in new user agents the styles of the parent page will be automatically
applied to the contents of the frame, but to support legacy user agents authors might wish to include the
styles explicitly.
p51 component of the URL p51 of the specified resource (after any redirects)
matches a pattern that a plugin p27 supports, then the content's type p207 is the type that that plugin can
handle.
For example, a plugin might say that it can handle resources with p51 components that end
with the four character string ".swf".
3.
Otherwise, if the specified resource has explicit Content-Type metadata p57 , then that is the content's
type p207 .
4.
Otherwise, the content has no type and there can be no appropriate plugin p27 for it.
The embed p205 element has no fallback content p92 . If the user agent can't find a suitable plugin, then the user agent
must use a default plugin. (This default could be as simple as saying "Unsupported Format".)
Whether the resource is fetched successfully or not (e.g. whether the response code was a 2xx code or
equivalent p56 ) must be ignored when determining the resource's type and when handing the resource to the
plugin.
Note: This allows servers to return data for plugins even with error responses (e.g. HTTP 500
Internal Server Error codes can still contain plugin data).
Any namespace-less attribute other than name p662 , align p664 , hspace p664 , and vspace p664 may be specified on the
embed p205 element, so long as its name is XML-compatible p27 and contains no characters in the range U+0041 to
U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z). These attributes are then passed as parameters to
the plugin p27 .
Note: All attributes in HTML documents p71 get lowercased automatically, so the restriction on
uppercase letters doesn't affect such documents.
207
Note: The four exceptions are to exclude legacy attributes that have side-effects beyond just
sending parameters to the plugin p27 .
The user agent should pass the names and values of all the attributes of the embed p205 element that have no
namespace to the plugin p27 used, when it is instantiated.
If the plugin p27 instantiated for the embed p205 element supports a scriptable interface, the HTMLEmbedElement p206
object representing the element should expose that interface while the element is instantiated.
The embed p205 element supports dimension attributes p271 .
The IDL attributes src and type each must reflect p57 the respective content attributes of the same name.
Here's a way to embed a resource that requires a proprietary plug-in, like Flash:
If the user does not have the plug-in (for example if the plug-in vendor doesn't support the user's platform),
then the user will be unable to use the resource.
To pass the plugin a parameter "quality" with the value "high", an attribute can be specified:
This would be equivalent to the following, when using an object p208 element instead:
4.8.4 The object element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
If the element has a usemap p268 attribute: Interactive content p92 .
Listed p297 , submittable p297 , form-associated element p297 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
Zero or more param p213 elements, then, transparent p93 .
Content attributes:
Global attributes p82
data p209
type p209
name p209
usemap p268
form p353
width p271
height p271
DOM interface:
interface HTMLObjectElement : HTMLElement {
attribute DOMString data;
attribute DOMString type;
attribute DOMString name;
attribute DOMString useMap;
readonly attribute HTMLFormElement form;
attribute DOMString width;
attribute DOMString height;
readonly attribute Document contentDocument;
readonly attribute WindowProxy contentWindow;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
208
boolean checkValidity();
void setCustomValidity(in DOMString error);
};
Depending on the type of content instantiated by the object p208 element, the node also supports other
interfaces.
The object p208 element can represent an external resource, which, depending on the type of the resource, will
either be treated as an image, as a nested browsing context p439 , or as an external resource to be processed by a
plugin p27 .
The data attribute, if present, specifies the address of the resource. If present, the attribute must be a valid nonempty URL p51 .
The type attribute, if present, specifies the type of the resource. If present, the attribute must be a valid MIME
type p26 .
At least one of either the data p209 attribute or the type p209 attribute must be present.
The name attribute, if present, must be a valid browsing context name p442 . The given value is used to name the
nested browsing context p439 , if applicable.
When the element is created, when it is popped off the stack of open elements p563 of an HTML parser p554 or XML
parser p635 , and subsequently whenever the element is inserted into a document p27 or removed from a
document p27 ; and whenever the element's Document p31 changes whether it is fully active p440 ; and whenever an
ancestor object p208 element changes to or from showing its fallback content p92 ; and whenever the element's
classid p662 attribute is set, changed, or removed; and, when its classid p662 attribute is not present, whenever its
data p209 attribute is set, changed, or removed; and, when neither its classid p662 attribute nor its data p209 attribute
are present, whenever its type p209 attribute is set, changed, or removed: the user agent must queue a task p490 to
run the following steps to (re)determine what the object p208 element represents. The task source p490 for this
task p489 is the DOM manipulation task source p491 .
1.
If the user has indicated a preference that this object p208 element's fallback content p92 be shown
instead of the element's usual behavior, then jump to the last step in the overall set of steps (fallback).
Note: For example, a user could ask for the element's fallback content p92 to be shown
because that content uses a format that the user finds more accessible.
2.
If the element has an ancestor media element p219 , or has an ancestor object p208 element that is not
showing its fallback content p92 , or if the element is not in a Document p27 with a browsing context p439 , or if
the element's Document p31 is not fully active p440 , or if the element is still in the stack of open
elements p563 of an HTML parser p554 or XML parser p635 , then jump to the last step in the overall set of
steps (fallback).
3.
If the classid p662 attribute is present, and has a value that isn't the empty string, then: if the user agent
can find a plugin p27 suitable according to the value of the classid p662 attribute, and plugins aren't being
sandboxed p211 , then that plugin p27 should be used p211 , and the value of the data p209 attribute, if any,
should be passed to the plugin p27 . If no suitable plugin p27 can be found, or if the plugin p27 reports an
error, jump to the last step in the overall set of steps (fallback).
4.
If the data p209 attribute is present and its value is not the empty string, then:
1.
If the type p209 attribute is present and its value is not a type that the user agent supports, and
is not a type that the user agent can find a plugin p27 for, then the user agent may jump to the
last step in the overall set of steps (fallback) without fetching the content to examine its real
type.
2.
Resolve p51 the URL p51 specified by the data p209 attribute, relative to the element.
3.
If that failed, fire a simple event p496 named error at the element, then jump to the last step in
the overall set of steps (fallback).
4.
Fetch p55 the resulting absolute URL p52 , from the element's browsing context scope origin p441 if
it has one.
Fetching the resource must delay the load event p619 of the element's document until the
task p489 that is queued p490 by the networking task source p491 once the resource has been
fetched p55 (defined next) has been run.
209
5.
If the resource is not yet available (e.g. because the resource was not available in the cache,
so that loading the resource required making a request over the network), then jump to the
last step in the overall set of steps (fallback). The task p489 that is queued p490 by the networking
task source p491 once the resource is available must restart this algorithm from this step.
Resources can load incrementally; user agents may opt to consider a resource "available"
whenever enough data has been obtained to begin processing the resource.
6.
If the load failed (e.g. there was an HTTP 404 error, there was a DNS error), fire a simple
event p496 named error at the element, then jump to the last step in the overall set of steps
(fallback).
7.
Determine the resource type, as follows:
1.
Let the resource type be unknown.
2.
Let the sniffed flag be false.
3.
If the user agent is configured to strictly obey Content-Type headers for this
resource, and the resource has associated Content-Type metadata p57 , then let the
resource type be the type specified in the resource's Content-Type metadata p57 , and
abort these substeps.
4.
If there is a type p209 attribute present on the object p208 element, and that attribute's
value is not a type that the user agent supports, but it is a type that a plugin p27
supports, then let the resource type be the type specified in that type p209 attribute.
5.
Otherwise, if the resource type is unknown, and the resource has associated
Content-Type metadata p57 , then let the resource type be the type specified in the
resource's Content-Type metadata p57 .
If this results in the resource type being "text/plain", then let the resource type be
the result of applying the rules for distingushing if a resource is text or binary p57 to
the resource instead, and then set the sniffed flag to true.
6.
If the resource type is unknown or "application/octet-stream" at this point and
there is a type p209 attribute present on the object p208 element, then change the
resource type to instead be the type specified in that type p209 attribute.
Otherwise, if the resource type is "application/octet-stream" but there is no
type p209 attribute on the object p208 element, then change the resource type to be
unknown, so that the sniffing rules in the following steps are invoked.
7.
If the resource type is still unknown at this point, but the p51 component of
the URL p51 of the specified resource (after any redirects) matches a pattern that a
plugin p27 supports, then let resource type be the type that that plugin can handle.
For example, a plugin might say that it can handle resources with p51
components that end with the four character string ".swf".
8.
If the resource type is still unknown, and the sniffed flag is false, then change the
resource type to instead be the sniffed type of the resource p57 .
Otherwise, if the resource type is still unknown, and the sniffed flag is true, then
change the resource type back to text/plain.
8.
Handle the content as given by the first of the following cases that matches:
↪ If the resource type is not a type that the user agent supports, but it is a type
that a plugin p27 supports
If plugins are being sandboxed p211 , jump to the last step in the overall set of steps
(fallback).
Otherwise, the user agent should use the plugin that supports resource type p211 and
pass the content of the resource to that plugin p27 . If the plugin p27 reports an error,
then jump to the last step in the overall set of steps (fallback).
p27
↪ If the resource type is an XML MIME type , or if the resource type does not
start with "image/"
The object p208 element must be associated with a newly created nested browsing
context p439 , if it does not already have one.
If the URL p51 of the given resource is not about:blank p56 , the element's nested
browsing context p439 must then be navigated p459 to that resource, with replacement
210
enabled p466 , and with the object p208 element's document's browsing context p439 as
the source browsing context p459 . (The data p209 attribute of the object p208 element
doesn't get updated if the browsing context gets further navigated to other
locations.)
If the URL p51 of the given resource is about:blank p56 , then, instead, the user agent
must queue a task p490 to fire a simple event p496 named load at the object p208
element.
The object p208 element represents p638 the nested browsing context p439 .
If the name p209 attribute is present, the browsing context name p442 must be set to the
value of this attribute; otherwise, the browsing context name p442 must be set to the
empty string.
Note: It's possible that the navigation p459 of the browsing
context p439 will actually obtain the resource from a different
application cache p471 . Even if the resource is then found to have a
different type, it is still used as part of a nested browsing
context p439 ; this algorithm doesn't restart with the new resource.
↪ If the resource type starts with "image/", and support for images has not been
disabled
Apply the image sniffing p57 rules to determine the type of the image.
The object p208 element represents p638 the specified image. The image is not a
nested browsing context p439 .
If the image cannot be rendered, e.g. because it is malformed or in an unsupported
format, jump to the last step in the overall set of steps (fallback).
↪ Otherwise
The given resource type is not supported. Jump to the last step in the overall set of
steps (fallback).
9.
10.
The element's contents are not part of what the object p208 element represents.
Once the resource is completely loaded, queue a task p490 to fire a simple event p496 named
load at the element.
The task source p490 for this task is the DOM manipulation task source p491 .
5.
If the data p209 attribute is absent but the type p209 attribute is present, plugins aren't being
sandboxed p211 , and the user agent can find a plugin p27 suitable according to the value of the type p209
attribute, then that plugin p27 should be used p211 . If no suitable plugin p27 can be found, or if the plugin p27
reports an error, jump to the next step (fallback).
6.
(Fallback.) The object p208 element represents p638 the element's children, ignoring any leading param p213
element children. This is the element's fallback content p92 . If the element has an instantiated plugin p27 ,
then unload it.
When the algorithm above instantiates a plugin p27 , the user agent should pass to the plugin p27 used the names
and values of all the attributes on the element, in the order they were added to the element, with the attributes
added by the parser being ordered in source order, followed by a parameter named "PARAM" whose value is null,
followed by all the names and values of parameters p213 given by param p213 elements that are children of the
object p208 element, in tree order p27 . If the plugin p27 supports a scriptable interface, the HTMLObjectElement p208
object representing the element should expose that interface. The object p208 element represents p638 the plugin p27 .
The plugin p27 is not a nested browsing context p439 .
If either:
•
the sandboxed plugins browsing context flag p202 was set on the object p208 element's Document p31 's
browsing context p439 when the Document p31 was created, or
•
the object p208 element's Document p31 was parsed from a resource whose sniffed type p57 as determined
during navigation p459 is text/html-sandboxed p679
...then the steps above must always act as if they had failed to find a plugin p27 , even if one would otherwise have
been used.
211
Note: The above algorithm is independent of CSS properties (including 'display', 'overflow',
and 'visibility'). For example, it runs even if the element is hidden with a 'display:none' CSS
style, and does not run again if the element's visibility changes.
Due to the algorithm above, the contents of object p208 elements act as fallback content p92 , used only when
referenced resources can't be shown (e.g. because it returned a 404 error). This allows multiple object p208
elements to be nested inside each other, targeting multiple user agents with different capabilities, with the user
agent picking the first one it supports.
Whenever the name p209 attribute is set, if the object p208 element has a nested browsing context p439 , its name p442
must be changed to the new value. If the attribute is removed, if the object p208 element has a browsing
context p439 , the browsing context name p442 must be set to the empty string.
The usemap p268 attribute, if present while the object p208 element represents an image, can indicate that the object
has an associated image map p268 . The attribute must be ignored if the object p208 element doesn't represent an
image.
The form p353 attribute is used to explicitly associate the object p208 element with its form owner p353 .
Constraint validation: object p208 elements are always barred from constraint validation p356 .
The object p208 element supports dimension attributes p271 .
The IDL attributes data, type, name, and useMap each must reflect p57 the respective content attributes of the same
name.
The contentDocument IDL attribute must return the Document p31 object of the active document p439 of the
object p208 element's nested browsing context p439 , if it has one; otherwise, it must return null.
The contentWindow IDL attribute must return the WindowProxy p449 object of the object p208 element's nested
browsing context p439 , if it has one; otherwise, it must return null.
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 .
In the following example, a Java applet is embedded in a page using the object p208 element. (Generally
speaking, it is better to avoid using applets like these and instead use native JavaScript and HTML to provide
the functionality, since that way the application will work on all Web browsers without requiring a third-party
plugin. Many devices, especially embedded devices, do not support third-party technologies like Java.)
You do not have Java available, or it is disabled.
My Java Clock
In this example, an HTML page is embedded in another using the object p208 element.
My HTML Clock
The following example shows how a plugin can be used in HTML (in this case the Flash plugin, to show a
video file). Fallback is provided for users who do not have Flash enabled, in this case using the video p213
element to show the video for those using user agents that support video p213 , and finally providing a link to
the video for those who have neither Flash nor a video p213 -capable browser.
Look at my video:
View video .
212
4.8.5 The param element
Categories
None.
Contexts in which this element may be used:
As a child of an object p208 element, before any flow content p91 .
Content model:
Empty.
Content attributes:
Global attributes p82
name p213
value p213
DOM interface:
interface HTMLParamElement : HTMLElement {
attribute DOMString name;
attribute DOMString value;
};
The param p213 element defines parameters for plugins invoked by object p208 elements. It does not represent p638
anything on its own.
The name attribute gives the name of the parameter.
The value attribute gives the value of the parameter.
Both attributes must be present. They may have any value.
If both attributes are present, and if the parent element of the param p213 is an object p208 element, then the
element defines a parameter with the given name/value pair.
The IDL attributes name and value must both reflect p57 the respective content attributes of the same name.
The following example shows how the param p213 element can be used to pass a parameter to a plugin, in
this case the O3D plugin.
O3D test page
4.8.6 The video element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
If the element has a controls p235 attribute: Interactive content p92 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
If the element has a src p220 attribute: transparent p93 , but with no media element p219 descendants.
213
If the element does not have a src p220 attribute: one or more source p217 elements, then, transparent p93 ,
but with no media element p219 descendants.
Content attributes:
Global attributes p82
src p220
poster p214
preload p227
autoplay p231
loop p229
controls p235
width p271
height p271
DOM interface:
interface HTMLVideoElement : HTMLMediaElement {
attribute DOMString width;
attribute DOMString height;
readonly attribute unsigned long videoWidth;
readonly attribute unsigned long videoHeight;
attribute DOMString poster;
};
A video p213 element is used for playing videos or movies.
Content may be provided inside the video p213 element. User agents should not show this content to the user; it is
intended for older Web browsers which do not support video p213 , so that legacy video plugins can be tried, or to
show text to the users of these older browsers informing them of how to access the video contents.
Note: In particular, this content is not intended to address accessibility concerns. To make
video content accessible to the blind, deaf, and those with other physical or cognitive
disabilities, authors are expected to provide alternative media streams and/or to embed
accessibility aids (such as caption or subtitle tracks, audio description tracks, or signlanguage overlays) into their media streams.
The video p213 element is a media element p219 whose media data p219 is ostensibly video data, possibly with
associated audio data.
The src p220 , preload p227 , autoplay p231 , loop p229 , and controls p235 attributes are the attributes common to all
media elements p219 .
The poster attribute gives the address of an image file that the user agent can show while no video data is
available. The attribute, if present, must contain a valid non-empty URL p51 . If the specified resource is to be used,
then, when the element is created or when the poster p214 attribute is set, if its value is not the empty string, its
value must be resolved p51 relative to the element, and if that is successful, the resulting absolute URL p52 must be
fetched p55 , from the element's Document p31 's origin p449 ; this must delay the load event p619 of the element's
document. The poster frame is then the image obtained from that resource, if any.
Note: The image given by the poster p214 attribute, the poster frame p214 , is intended to be a
representative frame of the video (typically one of the first non-blank frames) that gives the
user an idea of what the video is like.
The poster IDL attribute must reflect p57 the poster p214 content attribute.
When no video data is available (the element's readyState p231 attribute is either HAVE_NOTHING p229 , or
HAVE_METADATA p229 but no video data has yet been obtained at all), the video p213 element represents p638 either the
poster frame p214 , or nothing.
When a video p213 element is paused p231 and the current playback position p229 is the first frame of video, the
element represents p638 either the frame of video corresponding to the current playback position p229 or the poster
frame p214 , at the discretion of the user agent.
Notwithstanding the above, the poster frame p214 should be preferred over nothing, but the poster frame p214 should
not be shown again after a frame of video has been shown.
214
When a video p213 element is paused p231 at any other position, the element represents p638 the frame of video
corresponding to the current playback position p229 , or, if that is not yet available (e.g. because the video is seeking
or buffering), the last frame of the video to have been rendered.
When a video p213 element is potentially playing p231 , it represents p638 the frame of video at the continuously
increasing "current" position p229 . When the current playback position p229 changes such that the last frame
rendered is no longer the frame corresponding to the current playback position p229 in the video, the new frame
must be rendered. Similarly, any audio associated with the video must, if played, be played synchronized with the
current playback position p229 , at the specified volume p236 with the specified mute state p236 .
When a video p213 element is neither potentially playing p231 nor paused p231 (e.g. when seeking or stalled), the
element represents p638 the last frame of the video to have been rendered.
Note: Which frame in a video stream corresponds to a particular playback position is defined
by the video stream's format.
In addition to the above, the user agent may provide messages to the user (such as "buffering", "no video loaded",
"error", or more detailed information) by overlaying text or icons on the video or other areas of the element's
playback area, or in another appropriate manner.
User agents that cannot render the video may instead make the element represent p638 a link to an external video
playback utility or to the video data itself.
This box is non-normative. Implementation requirements are given below this box.
video . videoWidth
p215
video . videoHeight p215
These attributes return the intrinsic dimensions of the video, or zero if the dimensions are not known.
The intrinsic width and intrinsic height of the media resource p219 are the dimensions of the resource in CSS
pixels after taking into account the resource's dimensions, aspect ratio, clean aperture, resolution, and so forth, as
defined for the format used by the resource. If an anamorphic format does not define how to apply the aspect ratio
to the video data's dimensions to obtain the "correct" dimensions, then the user agent must apply the ratio by
increasing one dimension and leaving the other unchanged.
The videoWidth IDL attribute must return the intrinsic width p215 of the video in CSS pixels. The videoHeight IDL
attribute must return the intrinsic height p215 of the video in CSS pixels. If the element's readyState p231 attribute is
HAVE_NOTHING p229 , then the attributes must return 0.
The video p213 element supports dimension attributes p271 .
Video content should be rendered inside the element's playback area such that the video content is shown
centered in the playback area at the largest possible size that fits completely within it, with the video content's
aspect ratio being preserved. Thus, if the aspect ratio of the playback area does not match the aspect ratio of the
video, the video will be shown letterboxed or pillarboxed. Areas of the element's playback area that do not contain
the video represent nothing.
The intrinsic width of a video p213 element's playback area is the intrinsic width p215 of the video resource, if that is
available; otherwise it is the intrinsic width of the poster frame p214 , if that is available; otherwise it is 300 CSS
pixels.
The intrinsic height of a video p213 element's playback area is the intrinsic height p215 of the video resource, if that is
available; otherwise it is the intrinsic height of the poster frame p214 , if that is available; otherwise it is 150 CSS
pixels.
User agents should provide controls to enable or disable the display of closed captions, audio description tracks,
and other additional data associated with the video stream, though such features should, again, not interfere with
the page's normal rendering.
User agents may allow users to view the video content in manners more suitable to the user (e.g. full-screen or in
an independent resizable window). As for the other user interface features, controls to enable this should not
interfere with the page's normal rendering unless the user agent is exposing a user interface p235 . In such an
independent context, however, user agents may make full user interfaces visible, with, e.g., play, pause, seeking,
and volume controls, even if the controls p235 attribute is absent.
User agents may allow video playback to affect system features that could interfere with the user's experience; for
example, user agents could disable screensavers while video playback is in progress.
⚠Warning! User agents should not provide a public API to cause videos to be shown full-screen. A
script, combined with a carefully crafted video file, could trick the user into thinking a system-modal
215
dialog had been shown, and prompt the user for a password. There is also the danger of "mere"
annoyance, with pages launching full-screen videos when links are clicked or pages navigated.
Instead, user-agent-specific interface features may be provided to easily allow the user to obtain a
full-screen playback mode.
This example shows how to detect when a video has failed to play correctly:
Download the video file .
4.8.7 The audio element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
If the element has a controls p235 attribute: Interactive content p92 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
If the element has a src p220 attribute: transparent p93 , but with no media element p219 descendants.
If the element does not have a src p220 attribute: one or more source p217 elements, then, transparent p93 ,
but with no media element p219 descendants.
Content attributes:
Global attributes p82
src p220
preload p227
autoplay p231
loop p229
controls p235
DOM interface:
[NamedConstructor=Audio(),
NamedConstructor=Audio(in DOMString src)]
interface HTMLAudioElement : HTMLMediaElement {};
An audio p216 element represents p638 a sound or audio stream.
Content may be provided inside the audio p216 element. User agents should not show this content to the user; it is
intended for older Web browsers which do not support audio p216 , so that legacy audio plugins can be tried, or to
show text to the users of these older browsers informing them of how to access the audio contents.
216
Note: In particular, this content is not intended to address accessibility concerns. To make
audio content accessible to the deaf or to those with other physical or cognitive disabilities,
authors are expected to provide alternative media streams and/or to embed accessibility aids
(such as transcriptions) into their media streams.
The audio p216 element is a media element p219 whose media data p219 is ostensibly audio data.
The src p220 , preload p227 , autoplay p231 , loop p229 , and controls p235 attributes are the attributes common to all
media elements p219 .
When an audio p216 element is potentially playing p231 , it must have its audio data played synchronized with the
current playback position p229 , at the specified volume p236 with the specified mute state p236 .
When an audio p216 element is not potentially playing p231 , audio must not play for the element.
This box is non-normative. Implementation requirements are given below this box.
audio = new Audio p217 ( [ url ] )
Returns a new audio p216 element, with the src p220 attribute set to the value passed in the argument, if
applicable.
Two constructors are provided for creating HTMLAudioElement p216 objects (in addition to the factory methods from
DOM Core such as createElement()): Audio() and Audio(src). When invoked as constructors, these must return
a new HTMLAudioElement p216 object (a new audio p216 element). The element must have its preload p227 attribute
set to the literal value "auto p227 ". If the src argument is present, the object created must have its src p220 content
attribute set to the provided value, and the user agent must invoke the object's resource selection algorithm p223
before returning. The element's document must be the active document p439 of the browsing context p439 of the
Window p443 object on which the interface object of the invoked constructor is found.
4.8.8 The source element
Categories
None.
Contexts in which this element may be used:
As a child of a media element p219 , before any flow content p91 .
Content model:
Empty.
Content attributes:
Global attributes p82
src p217
type p217
media p218
DOM interface:
interface HTMLSourceElement : HTMLElement {
attribute DOMString src;
attribute DOMString type;
attribute DOMString media;
};
The source p217 element allows authors to specify multiple alternative media resources p219 for media elements p219 .
It does not represent p638 anything on its own.
The src attribute gives the address of the media resource p219 . The value must be a valid non-empty URL p51 . This
attribute must be present.
The type attribute gives the type of the media resource p219 , to help the user agent determine if it can play this
media resource p219 before fetching it. If specified, its value must be a valid MIME type p26 . The codecs parameter
may be specified and might be necessary to specify exactly how the resource is encoded. [RFC4281] p703
The following list shows some examples of how to use the codecs= MIME parameter in the type p217
attribute.
217
H.264 Simple baseline profile video (main and extended video compatible) level 3 and LowComplexity AAC audio in MP4 container
H.264 Extended profile video (baseline-compatible) level 3 and Low-Complexity AAC audio in
MP4 container
H.264 Main profile video level 3 and Low-Complexity AAC audio in MP4 container
H.264 'High' profile video (incompatible with main, baseline, or extended profiles) level 3 and
Low-Complexity AAC audio in MP4 container
MPEG-4 Visual Simple Profile Level 0 video and Low-Complexity AAC audio in MP4 container
MPEG-4 Advanced Simple Profile Level 0 video and Low-Complexity AAC audio in MP4 container
MPEG-4 Visual Simple Profile Level 0 video and AMR audio in 3GPP container
Theora video and Vorbis audio in Ogg container
Theora video and Speex audio in Ogg container
Vorbis audio alone in Ogg container
Speex audio alone in Ogg container
FLAC audio alone in Ogg container
Dirac video and Vorbis audio in Ogg container
Theora video and Vorbis audio in Matroska container
The media attribute gives the intended media type of the media resource p219 , to help the user agent determine if
this media resource p219 is useful to the user before fetching it. Its value must be a valid media query p51 .
The default, if the media attribute is omitted, is "all", meaning that by default the media resource p219 is suitable
for all media.
If a source p217 element is inserted as a child of a media element p219 that has no src p220 attribute and whose
networkState p222 has the value NETWORK_EMPTY p222 , the user agent must invoke the media element p219 's resource
selection algorithm p223 .
The IDL attributes src, type, and media must reflect p57 the respective content attributes of the same name.
If the author isn't sure if the user agents will all be able to render the media resources provided, the author
can listen to the error event on the last source p217 element and trigger fallback behavior:
...
4.8.9 Media elements
Media elements implement the following interface:
interface HTMLMediaElement : HTMLElement {
// error state
readonly attribute MediaError error;
// network state
attribute DOMString src;
readonly attribute DOMString currentSrc;
const unsigned short NETWORK_EMPTY = 0;
const unsigned short NETWORK_IDLE = 1;
const unsigned short NETWORK_LOADING = 2;
const unsigned short NETWORK_NO_SOURCE = 3;
readonly attribute unsigned short networkState;
attribute DOMString preload;
readonly attribute TimeRanges buffered;
void load();
DOMString canPlayType(in DOMString type);
// ready state
const unsigned short HAVE_NOTHING = 0;
const unsigned short HAVE_METADATA = 1;
const unsigned short HAVE_CURRENT_DATA = 2;
const unsigned short HAVE_FUTURE_DATA = 3;
const unsigned short HAVE_ENOUGH_DATA = 4;
readonly attribute unsigned short readyState;
readonly attribute boolean seeking;
// playback state
attribute
readonly attribute
readonly attribute
readonly attribute
attribute
attribute
readonly attribute
readonly attribute
readonly attribute
attribute
attribute
void play();
void pause();
float currentTime;
float startTime;
float duration;
boolean paused;
float defaultPlaybackRate;
float playbackRate;
TimeRanges played;
TimeRanges seekable;
boolean ended;
boolean autoplay;
boolean loop;
// controls
attribute boolean controls;
attribute float volume;
attribute boolean muted;
};
The media element attributes, src p220 , preload p227 , autoplay p231 , loop p229 , and controls p235 , apply to all media
elements p219 . They are defined in this section.
Media elements p219 are used to present audio data, or video and audio data, to the user. This is referred to as
media data in this section, since this section applies equally to media elements p219 for audio or for video. The
term media resource is used to refer to the complete set of media data, e.g. the complete video file, or complete
audio file.
Except where otherwise specified, the task source p490 for all the tasks queued p490 in this section and its
subsections is the media element event task source.
219
4.8.9.1 Error codes
This box is non-normative. Implementation requirements are given below this box.
media . error
p220
Returns a MediaError p220 object representing the current error state of the element.
Returns null if there is no error.
All media elements p219 have an associated error status, which records the last error the element encountered
since its resource selection algorithm p223 was last invoked. The error attribute, on getting, must return the
MediaError p220 object created for this last error, or null if there has not been an error.
interface MediaError {
const unsigned short MEDIA_ERR_ABORTED = 1;
const unsigned short MEDIA_ERR_NETWORK = 2;
const unsigned short MEDIA_ERR_DECODE = 3;
const unsigned short MEDIA_ERR_SRC_NOT_SUPPORTED = 4;
readonly attribute unsigned short code;
};
This box is non-normative. Implementation requirements are given below this box.
media . error
p220
. code p220
Returns the current error's error code, from the list below.
The code attribute of a MediaError p220 object must return the code for the error, which must be one of the
following:
MEDIA_ERR_ABORTED (numeric value 1)
The fetching process for the media resource p219 was aborted by the user agent at the user's request.
MEDIA_ERR_NETWORK (numeric value 2)
A network error of some description caused the user agent to stop fetching the media resource p219 , after the
resource was established to be usable.
MEDIA_ERR_DECODE (numeric value 3)
An error of some description occurred while decoding the media resource p219 , after the resource was
established to be usable.
MEDIA_ERR_SRC_NOT_SUPPORTED (numeric value 4)
The media resource p219 indicated by the src p220 attribute was not suitable.
4.8.9.2 Location of the media resource
The src content attribute on media elements p219 gives the address of the media resource (video, audio) to show.
The attribute, if present, must contain a valid non-empty URL p51 .
If a src p220 attribute of a media element p219 is set or changed, the user agent must invoke the media element p219 's
media element load algorithm p222 . (Removing the src p220 attribute does not do this, even if there are source p217
elements present.)
The src IDL attribute on media elements p219 must reflect p57 the content attribute of the same name.
This box is non-normative. Implementation requirements are given below this box.
media . currentSrc
p220
Returns the address of the current media resource p219 .
Returns the empty string when there is no media resource p219 .
The currentSrc IDL attribute is initially the empty string. Its value is changed by the resource selection
algorithm p223 defined below.
220
Note: There are two ways to specify a media resource p219 , the src p220 attribute, or source p217
elements. The attribute overrides the elements.
4.8.9.3 MIME types
A media resource p219 can be described in terms of its type, specifically a MIME type p26 , optionally with a codecs
parameter. [RFC4281] p703
Types are usually somewhat incomplete descriptions; for example "video/mpeg" doesn't say anything except what
the container type is, and even a type like "video/mp4; codecs="avc1.42E01E, mp4a.40.2"" doesn't include
information like the actual bitrate (only the maximum bitrate). Thus, given a type, a user agent can often only
know whether it might be able to play media of that type (with varying levels of confidence), or whether it
definitely cannot play media of that type.
A type that the user agent knows it cannot render is one that describes a resource that the user agent
definitely does not support, for example because it doesn't recognize the container type, or it doesn't support the
listed codecs.
The MIME type p26 "application/octet-stream" with no parameters is never a type that the user agent knows it
cannot render p221 . User agents must treat that type as equivalent to the lack of any explicit Content-Type
metadata p57 when it is used to label a potential media resource p219 .
Note: In the absence of a specification to the contrary, the MIME type p26 "application/octetstream" when used with parameters, e.g. "application/octet-stream;codecs=theora", is a type
that the user agent knows it cannot render p221 .
This box is non-normative. Implementation requirements are given below this box.
media . canPlayType
p221
(type)
Returns the empty string (a negative response), "maybe", or "probably" based on how confident the
user agent is that it can play media resources of the given type.
The canPlayType(type) method must return the empty string if type is a type that the user agent knows it cannot
render p221 ; it must return "probably" if the user agent is confident that the type represents a media resource p219
that it can render if used in with this audio p216 or video p213 element; and it must return "maybe" otherwise.
Implementors are encouraged to return "maybe" unless the type can be confidently established as being supported
or not. Generally, a user agent should never return "probably" if the type doesn't have a codecs parameter.
This script tests to see if the user agent supports a (fictional) new format to dynamically decide whether to
use a video p213 element or a plugin:
221
Note: The type p217 attribute of the source p217 element allows the user agent to avoid
downloading resources that use formats it cannot render.
4.8.9.4 Network states
This box is non-normative. Implementation requirements are given below this box.
media . networkState
p222
Returns the current state of network activity for the element, from the codes in the list below.
As media elements p219 interact with the network, their current network activity is represented by the
networkState attribute. On getting, it must return the current network state of the element, which must be one of
the following values:
NETWORK_EMPTY (numeric value 0)
The element has not yet been initialized. All attributes are in their initial states.
NETWORK_IDLE (numeric value 1)
The element's resource selection algorithm p223 is active and has selected a resource p219 , but it is not actually
using the network at this time.
NETWORK_LOADING (numeric value 2)
The user agent is actively trying to download data.
NETWORK_NO_SOURCE (numeric value 3)
The element's resource selection algorithm p223 is active, but it has failed to find a resource p219 to use.
The resource selection algorithm p223 defined below describes exactly when the networkState p222 attribute
changes value and what events fire to indicate changes in this state.
4.8.9.5 Loading the media resource
This box is non-normative. Implementation requirements are given below this box.
media . load p222 ()
Causes the element to reset and start selecting and loading a new media resource p219 from scratch.
All media elements p219 have an autoplaying flag, which must begin in the true state, and a delaying-the-loadevent flag, which must begin in the false state. While the delaying-the-load-event flag p222 is true, the element
must delay the load event p619 of its document.
When the load() method on a media element p219 is invoked, the user agent must run the media element load
algorithm p222 .
The media element load algorithm consists of the following steps.
1.
Abort any already-running instance of the resource selection algorithm p223 for this element.
2.
If there are any tasks p489 from the media element p219 's media element event task source p219 in one of the
task queues p489 , then remove those tasks.
Note: Basically, pending events and callbacks for the media element are discarded
when the media element starts loading a new resource.
222
3.
If the media element p219 's networkState p222 is set to NETWORK_LOADING p222 or NETWORK_IDLE p222 , queue a
task p490 to fire a simple event p496 named abort p237 at the media element p219 .
4.
If the media element p219 's networkState p222 is not set to NETWORK_EMPTY p222 , then run these substeps:
1.
If a fetching process is in progress for the media element p219 , the user agent should stop it.
2.
Set the networkState p222 attribute to NETWORK_EMPTY p222 .
3.
If readyState p231 is not set to HAVE_NOTHING p229 , then set it to that state.
4.
If the paused p231 attribute is false, then set to true.
5.
If seeking p234 is true, set it to false.
6.
Set the current playback position p229 to 0.
7.
Queue a task p490 to fire a simple event p496 named emptied p237 at the media element p219 .
5.
Set the playbackRate p232 attribute to the value of the defaultPlaybackRate p232 attribute.
6.
Set the error p220 attribute to null and the autoplaying flag p222 to true.
7.
Invoke the media element p219 's resource selection algorithm p223 .
8.
Note: Playback of any previously playing media resource p219 for this element stops.
The resource selection algorithm for a media element p219 is as follows. This algorithm is always invoked
synchronously, but one of the first steps in the algorithm is to return and continue running the remaining steps
asynchronously, meaning that it runs in the background with scripts and other tasks p489 running in parallel. In
addition, this algorithm interacts closely with the event loop p489 mechanism; in particular, it has synchronous
sections p490 (which are triggered as part of the event loop p489 algorithm). Steps in such sections are marked with ?.
1.
Set the networkState p222 to NETWORK_NO_SOURCE p222 .
2.
Asynchronously await a stable state p490 , allowing the task p489 that invoked this algorithm to continue.
The synchronous section p490 consists of all the remaining steps of this algorithm until the algorithm says
the synchronous section p490 has ended. (Steps in synchronous sections p490 are marked with ?.)
3.
? If the media element p219 has a src p220 attribute, then let mode be attribute.
? Otherwise, if the media element p219 does not have a src p220 attribute but has a source p217 element
child, then let mode be children and let candidate be the first such source p217 element child in tree
order p27 .
? Otherwise the media element p219 has neither a src p220 attribute nor a source p217 element child: set the
networkState p222 to NETWORK_EMPTY p222 , and abort these steps; the synchronous section p490 ends.
4.
? Set the media element p219 's delaying-the-load-event flag p222 to true (this delays the load event p619 ),
and set its networkState p222 to NETWORK_LOADING p222 .
5.
? Queue a task p490 to fire a simple event p496 named loadstart p237 at the media element p219 .
6.
If mode is attribute, then run these substeps:
1.
? Process candidate: If the src p220 attribute's value is the empty string, then end the
synchronous section p490 , and jump down to the failed step below.
2.
? Let absolute URL be the absolute URL p52 that would have resulted from resolving p51 the
URL p51 specified by the src p220 attribute's value relative to the media element p219 when the
src p220 attribute was last changed.
3.
? If absolute URL was obtained successfully, set the currentSrc p220 attribute to absolute URL.
4.
End the synchronous section p490 , continuing the remaining steps asynchronously.
5.
If absolute URL was obtained successfully, run the resource fetch algorithm p225 with absolute
URL. If that algorithm returns without aborting this one, then the load failed.
6.
Failed: Reaching this step indicates that the media resource failed to load or that the given
URL p51 could not be resolved p51 . Set the error p220 attribute to a new MediaError p220 object
whose code p220 attribute is set to MEDIA_ERR_SRC_NOT_SUPPORTED p220 .
7.
Set the element's networkState p222 attribute to the NETWORK_NO_SOURCE p222 value.
8.
Queue a task p490 to fire a simple event p496 named error p237 at the media element p219 .
9.
Set the element's delaying-the-load-event flag p222 to false. This stops delaying the load
event p619 .
10.
Abort these steps. Until the load() p222 method is invoked or the src p220 attribute is changed,
the element won't attempt to load another resource.
Otherwise, the source p217 elements will be used; run these substeps:
1.
? Let pointer be a position defined by two adjacent nodes in the media element p219 's child list,
treating the start of the list (before the first child in the list, if any) and end of the list (after the
last child in the list, if any) as nodes in their own right. One node is the node before pointer,
223
and the other node is the node after pointer. Initially, let pointer be the position between the
candidate node and the next node, if there are any, or the end of the list, if it is the last node.
As nodes are inserted and removed into the media element p219 , pointer must be updated as
follows:
If a new node is inserted between the two nodes that define pointer
Let pointer be the point between the node before pointer and the new node. In other
words, insertions at pointer go after pointer.
If the node before pointer is removed
Let pointer be the point between the node after pointer and the node before the node
after pointer. In other words, pointer doesn't move relative to the remaining nodes.
If the node after pointer is removed
Let pointer be the point between the node before pointer and the node after the node
before pointer. Just as with the previous case, pointer doesn't move relative to the
remaining nodes.
Other changes don't affect pointer.
224
2.
? Process candidate: If candidate does not have a src p217 attribute, or if its src p217 attribute's
value is the empty string, then end the synchronous section p490 , and jump down to the failed
step below.
3.
? Let absolute URL be the absolute URL p52 that would have resulted from resolving p51 the
URL p51 specified by candidate's src p217 attribute's value relative to the candidate when the
src p217 attribute was last changed.
4.
? If absolute URL was not obtained successfully, then end the synchronous section p490 , and
jump down to the failed step below.
5.
? If candidate has a type p217 attribute whose value, when parsed as a MIME type p26 (including
any codecs described by the codecs parameter), represents a type that the user agent knows
it cannot render p221 , then end the synchronous section p490 , and jump down to the failed step
below.
6.
? If candidate has a media p218 attribute whose value does not match the environment p51 , then
end the synchronous section p490 , and jump down to the failed step below.
7.
? Set the currentSrc p220 attribute to absolute URL.
8.
End the synchronous section p490 , continuing the remaining steps asynchronously.
9.
Run the resource fetch algorithm p225 with absolute URL. If that algorithm returns without
aborting this one, then the load failed.
10.
Failed: Queue a task p490 to fire a simple event p496 named error at the candidate element, in
the context of the fetching process p55 that was used to try to obtain candidate's corresponding
media resource p219 in the resource fetch algorithm p225 .
11.
Asynchronously await a stable state p490 . The synchronous section p490 consists of all the
remaining steps of this algorithm until the algorithm says the synchronous section p490 has
ended. (Steps in synchronous sections p490 are marked with ?.)
12.
? Find next candidate: Let candidate be null.
13.
? Search loop: If the node after pointer is the end of the list, then jump to the waiting step
below.
14.
? If the node after pointer is a source p217 element, let candidate be that element.
15.
? Advance pointer so that the node before pointer is now the node that was after pointer, and
the node after pointer is the node after the node that used to be after pointer, if any.
16.
? If candidate is null, jump back to the search loop step. Otherwise, jump back to the process
candidate step.
17.
? Waiting: Set the element's networkState p222 attribute to the NETWORK_NO_SOURCE p222
value.
18.
? Set the element's delaying-the-load-event flag p222 to false. This stops delaying the load
event p619 .
19.
End the synchronous section p490 , continuing the remaining steps asynchronously.
20.
Wait until the node after pointer is a node other than the end of the list. (This step might wait
forever.)
21.
Asynchronously await a stable state p490 . The synchronous section p490 consists of all the
remaining steps of this algorithm until the algorithm says the synchronous section p490 has
ended. (Steps in synchronous sections p490 are marked with ?.)
22.
? Set the element's delaying-the-load-event flag p222 back to true (this delays the load event p619
again, in case it hasn't been fired yet).
23.
? Set the networkState p222 back to NETWORK_LOADING p222 .
24.
? Jump back to the find next candidate step above.
The resource fetch algorithm for a media element p219 and a given absolute URL p52 is as follows:
1.
Let the current media resource be the resource given by the absolute URL p52 passed to this algorithm.
This is now the element's media resource p219 .
2.
Begin to fetch p55 the current media resource, from the media element p219 's Document p31 's origin p449 .
Every 350ms (±200ms) or for every byte received, whichever is least frequent, queue a task p490 to fire a
simple event p496 named progress p237 at the element.
If at any point the user agent has received no data for more than about three seconds, then queue a
task p490 to fire a simple event p496 named stalled p237 at the element.
User agents may allow users to selectively block or slow media data p219 downloads. When a media
element p219 's download has been blocked altogether, the user agent must act as if it was stalled (as
opposed to acting as if the connection was closed). The rate of the download may also be throttled
automatically by the user agent, e.g. to balance the download with other connections sharing the same
bandwidth.
User agents may decide to not download more content at any time, e.g. after buffering five minutes of a
one hour media resource, while waiting for the user to decide whether to play the resource or not, or
while waiting for user input in an interactive resource. When a media element p219 's download has been
suspended, the user agent must set the networkState p222 to NETWORK_IDLE p222 and queue a task p490 to
fire a simple event p496 named suspend p237 at the element. If and when downloading of the resource
resumes, the user agent must set the networkState p222 to NETWORK_LOADING p222 .
Note: The preload p227 attribute provides a hint regarding how much buffering the
author thinks is advisable, even in the absence of the autoplay p231 attribute.
When a user agent decides to completely stall a download, e.g. if it is waiting until the user starts
playback before downloading any further content, the element's delaying-the-load-event flag p222 must
be set to false. This stops delaying the load event p619 .
The user agent may use whatever means necessary to fetch the resource (within the constraints put
forward by this and other specifications); for example, reconnecting to the server in the face of network
errors, using HTTP range retrieval requests, or switching to a streaming protocol. The user agent must
consider a resource erroneous only if it has given up trying to fetch it.
The networking task source p491 tasks p489 to process the data as it is being fetched must, when
appropriate, include the relevant substeps from the following list:
p219
cannot be fetched at all, due to network errors, causing the user
↪ If the media data
agent to give up trying to fetch the resource
p219
is found to have Content-Type metadata p57 that, when parsed as
↪ If the media resource
a MIME type p26 (including any codecs described by the codecs parameter), represents a
type that the user agent knows it cannot render p221 (even if the actual media data p219 is
in a supported format)
p219
can be fetched but is found by inspection to be in an unsupported
↪ If the media data
format, or can otherwise not be rendered at all
DNS errors, HTTP 4xx and 5xx errors (and equivalents in other protocols), and other fatal
network errors that occur before the user agent has established whether the current media
resource is usable, as well as the file using an unsupported container format, or using
unsupported codecs for all the data, must cause the user agent to execute the following steps:
1.
The user agent should cancel the fetching process.
2.
Abort this subalgorithm, returning to the resource selection algorithm p223 .
225
p219
has been fetched to determine the duration of the
↪ Once enough of the media data
p219
media resource
, its dimensions, and other metadata
This indicates that the resource is usable. The user agent must follow these substeps:
1.
Set the current playback position p229 to the earliest possible position p229 .
2.
Set the readyState p231 attribute to HAVE_METADATA p229 .
3.
For video p213 elements, set the videoWidth p215 and videoHeight p215 attributes.
4.
Set the duration p228 attribute to the duration of the resource.
Note: The user agent will p229 queue a task p490 to fire a simple
event p496 named durationchange p238 at the element at this point.
5.
Queue a task p490 to fire a simple event p496 named loadedmetadata p237 at the
element.
Note: Before this task is run, as part of the event loop mechanism,
the rendering will have been updated to resize the video p213 element
if appropriate.
6.
If either the media resource p219 or the address of the current media resource indicate
a particular start time, then seek p234 to that time. Ignore any resulting exceptions (if
the position is out of range, it is effectively ignored).
For example, a fragment identifier could be used to indicate a start position.
7.
Once the readyState p231 attribute reaches HAVE_CURRENT_DATA p230 , after the
loadeddata event has been fired p230 , set the element's delaying-the-load-event
flag p222 to false. This stops delaying the load event p619 .
Note: A user agent that is attempting to reduce network usage
while still fetching the metadata for each media resource p219 would
also stop buffering at this point, causing the networkState p222
attribute to switch to the NETWORK_IDLE p222 value.
Note: The user agent is required to determine the duration of the media
resource p219 and go through this step before playing.
p219
has been fetched p55 (but potentially before any of it
↪ Once the entire media resource
has been decoded)
Queue a task p490 to fire a simple event p496 named progress p237 at the media element p219 .
↪ If the connection is interrupted, causing the user agent to give up trying to fetch the
resource
Fatal network errors that occur after the user agent has established whether the current media
resource is usable must cause the user agent to execute the following steps:
1.
The user agent should cancel the fetching process.
2.
Set the error p220 attribute to a new MediaError p220 object whose code p220 attribute is
set to MEDIA_ERR_NETWORK p220 .
3.
Queue a task p490 to fire a simple event p496 named error p237 at the media element p219 .
4.
Set the element's networkState p222 attribute to the NETWORK_EMPTY p222 value and
queue a task p490 to fire a simple event p496 named emptied p237 at the element.
5.
Set the element's delaying-the-load-event flag p222 to false. This stops delaying the
load event p619 .
6.
Abort the overall resource selection algorithm p223 .
p219
is corrupted
↪ If the media data
Fatal errors in decoding the media data p219 that occur after the user agent has established
whether the current media resource is usable must cause the user agent to execute the
following steps:
1.
226
The user agent should cancel the fetching process.
2.
Set the error p220 attribute to a new MediaError p220 object whose code p220 attribute is
set to MEDIA_ERR_DECODE p220 .
3.
Queue a task p490 to fire a simple event p496 named error p237 at the media element p219 .
4.
Set the element's networkState p222 attribute to the NETWORK_EMPTY p222 value and
queue a task p490 to fire a simple event p496 named emptied p237 at the element.
5.
Set the element's delaying-the-load-event flag p222 to false. This stops delaying the
load event p619 .
6.
Abort the overall resource selection algorithm p223 .
p219
fetching process is aborted by the user
↪ If the media data
The fetching process is aborted by the user, e.g. because the user navigated the browsing
context to another page, the user agent must execute the following steps. These steps are not
followed if the load() p222 method itself is invoked while these steps are running, as the steps
above handle that particular kind of abort.
1.
The user agent should cancel the fetching process.
2.
Set the error p220 attribute to a new MediaError p220 object whose code p220 attribute is
set to MEDIA_ERR_ABORTED p220 .
3.
Queue a task p490 to fire a simple event p496 named abort p237 at the media element p219 .
4.
If the media element p219 's readyState p231 attribute has a value equal to
HAVE_NOTHING p229 , set the element's networkState p222 attribute to the
NETWORK_EMPTY p222 value and queue a task p490 to fire a simple event p496 named
emptied p237 at the element. Otherwise, set the element's networkState p222 attribute
to the NETWORK_IDLE p222 value.
5.
Set the element's delaying-the-load-event flag p222 to false. This stops delaying the
load event p619 .
6.
Abort the overall resource selection algorithm p223 .
p219
can be fetched but has non-fatal errors or uses, in part, codecs that
↪ If the media data
are unsupported, preventing the user agent from rendering the content completely
correctly but not preventing playback altogether
The server returning data that is partially usable but cannot be optimally rendered must cause
the user agent to render just the bits it can handle, and ignore the rest.
When the networking task source p491 has queued p490 the last task p489 as part of fetching p55 the media
resource p219 (i.e. once the download has completed), if the fetching process completes without errors,
including decoding the media data, and if all of the data is available to the user agent without network
access, then, the user agent must move on to the next step. This might never happen, e.g. when
streaming an infinite resource such as Web radio, or if the resource is longer than the user agent's ability
to cache data.
While the user agent might still need network access to obtain parts of the media resource p219 , the user
agent must remain on this step.
For example, if the user agent has discarded the first half of a video, the user agent will remain at
this step even once the playback has ended p231 , because there is always the chance the user will
seek back to the start. In fact, in this situation, once playback has ended p231 , the user agent will
end up dispatching a stalled p237 event, as described earlier.
3.
If the user agent ever reaches this step (which can only happen if the entire resource gets loaded and
kept available): abort the overall resource selection algorithm p223 .
The preload attribute is an enumerated attribute p34 . The following table lists the keywords and states for the
attribute — the keywords in the left column map to the states in the cell in the second column on the same row as
the keyword.
Keyword
none
State
None
metadata Metadata
auto
Brief description
Hints to the user agent that either the author does not expect the user to need the media resource, or that the
server wants to minimise unnecessary traffic.
Hints to the user agent that the author does not expect the user to need the media resource, but that fetching
the resource metadata (dimensions, first frame, track list, duration, etc) is reasonable.
Automatic Hints to the user agent that the user agent can put the user's needs first without risk to the server, up to and
including optimistically downloading the entire resource.
227
The empty string is also a valid keyword, and maps to the Automatic p227 state. The attribute's missing value
default is user-agent defined, though the Metadata p227 state is suggested as a compromise between reducing
server load and providing an optimal user experience.
The preload p227 attribute is intended to provide a hint to the user agent about what the author thinks will lead to
the best user experience. The attribute may be ignored altogether, for example based on explicit user preferences
or based on the available connectivity.
The preload IDL attribute must reflect p57 the content attribute of the same name.
Note: The autoplay p231 attribute can overrride the preload p227 attribute (since if the media
plays, it naturally has to buffer first, regardless of the hint given by the preload p227 attribute).
Including both is not an error, however.
This box is non-normative. Implementation requirements are given below this box.
media . buffered p228
Returns a TimeRanges p236 object that represents the ranges of the media resource p219 that the user
agent has buffered.
The buffered attribute must return a new static normalized TimeRanges object p236 that represents the ranges of
the media resource p219 , if any, that the user agent has buffered, at the time the attribute is evaluated. Users
agents must accurately determine the ranges available, even for media streams where this can only be
determined by tedious inspection.
Note: Typically this will be a single range anchored at the zero point, but if, e.g. the user
agent uses HTTP range requests in response to seeking, then there could be multiple ranges.
User agents may discard previously buffered data.
Note: Thus, a time position included within a range of the objects return by the buffered p228
attribute at one time can end up being not included in the range(s) of objects returned by the
same attribute at later times.
4.8.9.6 Offsets into the media resource
This box is non-normative. Implementation requirements are given below this box.
media . duration p228
Returns the length of the media resource p219 , in seconds.
Returns NaN if the duration isn't available.
Returns Infinity for unbounded streams.
media . currentTime p229 [ = value ]
Returns the current playback position p229 , in seconds.
Can be set, to seek to the given time.
Will throw an INVALID_STATE_ERR p70 exception if there is no selected media resource p219 . Will throw an
INDEX_SIZE_ERR p70 exception if the given time is not within the ranges to which the user agent can
seek.
media . startTime p229
Returns the earliest possible position p229 , in seconds. This is the time for the start of the current clip. It
might not be zero if the clip's timeline is not zero-based, or if the resource is a streaming resource (in
which case it gives the earliest time that the user agent is able to seek back to).
The duration attribute must return the length of the media resource p219 , in seconds. If no media data p219 is
available, then the attributes must return the Not-a-Number (NaN) value. If the media resource p219 is known to be
unbounded (e.g. a streaming radio), then the attribute must return the positive Infinity value.
The user agent must determine the duration of the media resource p219 before playing any part of the media
data p219 and before setting readyState p231 to a value equal to or greater than HAVE_METADATA p229 , even if doing so
requires seeking to multiple parts of the resource.
228
When the length of the media resource p219 changes (e.g. from being unknown to known, or from a previously
established length to a new length) the user agent must queue a task p490 to fire a simple event p496 named
durationchange p238 at the media element p219 .
If an "infinite" stream ends for some reason, then the duration would change from positive Infinity to the
time of the last frame or sample in the stream, and the durationchange p238 event would be fired. Similarly,
if the user agent initially estimated the media resource p219 's duration instead of determining it precisely,
and later revises the estimate based on new information, then the duration would change and the
durationchange p238 event would be fired.
Media elements p219 have a current playback position, which must initially be zero. The current position is a
time.
The currentTime attribute must, on getting, return the current playback position p229 , expressed in seconds. On
setting, the user agent must seek p234 to the new value (which might raise an exception).
If the media resource p219 is a streaming resource, then the user agent might be unable to obtain certain parts of
the resource after it has expired from its buffer. Similarly, some media resources p219 might have a timeline that
doesn't start at zero. The earliest possible position is the earliest position in the stream or resource that the
user agent can ever obtain again.
The startTime attribute must, on getting, return the earliest possible position p229 , expressed in seconds.
When the earliest possible position p229 changes, then: if the current playback position p229 is before the earliest
possible position p229 , the user agent must seek p234 to the earliest possible position p229 ; otherwise, if the user agent
has not fired a timeupdate p237 event at the element in the past 15 to 250ms and is not still running event handlers
for such an event, then the user agent must queue a task p490 to fire a simple event p496 named timeupdate p237 at
the element.
Note: Because of the above requirement and the requirement in the resource fetch
algorithm p225 that kicks in when the metadata of the clip becomes known p226 , the current
playback position p229 can never be less than the earliest possible position p229 .
User agents must act as if the timeline of the media resource p219 increases linearly starting from the earliest
possible position p229 , even if the underlying media data p219 has out-of-order or even overlapping time codes.
For example, if two clips have been concatenated into one video file, but the video format exposes the
original times for the two clips, the video data might expose a timeline that goes, say, 00:15..00:29 and
then 00:05..00:38. However, the user agent would not expose those times; it would instead expose the
times as 00:15..00:29 and 00:29..01:02, as a single video.
The loop attribute is a boolean attribute p34 that, if specified, indicates that the media element p219 is to seek back
to the start of the media resource p219 upon reaching the end.
The loop IDL attribute must reflect p57 the content attribute of the same name.
4.8.9.7 The ready states
This box is non-normative. Implementation requirements are given below this box.
media . readyState p231
Returns a value that expresses the current state of the element with respect to rendering the current
playback position p229 , from the codes in the list below.
Media elements p219 have a ready state, which describes to what degree they are ready to be rendered at the
current playback position p229 . The possible values are as follows; the ready state of a media element at any
particular time is the greatest value describing the state of the element:
HAVE_NOTHING (numeric value 0)
No information regarding the media resource p219 is available. No data for the current playback position p229 is
available. Media elements p219 whose networkState p222 attribute is NETWORK_EMPTY p222 are always in the
HAVE_NOTHING p229 state.
HAVE_METADATA (numeric value 1)
Enough of the resource has been obtained that the duration of the resource is available. In the case of a
video p213 element, the dimensions of the video are also available. The API will no longer raise an exception
when seeking. No media data p219 is available for the immediate current playback position p229 .
229
HAVE_CURRENT_DATA (numeric value 2)
Data for the immediate current playback position p229 is available, but either not enough data is available that
the user agent could successfully advance the current playback position p229 in the direction of playback p232 at
all without immediately reverting to the HAVE_METADATA p229 state, or there is no more data to obtain in the
direction of playback p232 . For example, in video this corresponds to the user agent having data from the
current frame, but not the next frame; and to when playback has ended p231 .
HAVE_FUTURE_DATA (numeric value 3)
Data for the immediate current playback position p229 is available, as well as enough data for the user agent
to advance the current playback position p229 in the direction of playback p232 at least a little without
immediately reverting to the HAVE_METADATA p229 state. For example, in video this corresponds to the user
agent having data for at least the current frame and the next frame. The user agent cannot be in this state if
playback has ended p231 , as the current playback position p229 can never advance in this case.
HAVE_ENOUGH_DATA (numeric value 4)
All the conditions described for the HAVE_FUTURE_DATA p230 state are met, and, in addition, the user agent
estimates that data is being fetched at a rate where the current playback position p229 , if it were to advance
at the rate given by the defaultPlaybackRate p232 attribute, would not overtake the available data before
playback reaches the end of the media resource p219 .
When the ready state of a media element p219 whose networkState p222 is not NETWORK_EMPTY p222 changes, the user
agent must follow the steps given below:
p229
, and the new ready state is HAVE_METADATA p229
↪ If the previous ready state was HAVE_NOTHING
Note: A loadedmetadata p237 DOM event will be fired p226 as part of the load() p222
algorithm.
p229
and the new ready state is HAVE_CURRENT_DATA p230
↪ If the previous ready state was HAVE_METADATA
or greater
If this is the first time this occurs for this media element p219 since the load() p222 algorithm was last
invoked, the user agent must queue a task p490 to fire a simple event p496 named loadeddata p237 at the
element.
If the new ready state is HAVE_FUTURE_DATA p230 or HAVE_ENOUGH_DATA p230 , then the relevant steps below
must then be run also.
p230
or more, and the new ready state is
↪ If the previous ready state was HAVE_FUTURE_DATA
p230
HAVE_CURRENT_DATA
or less
Note: A waiting p237 DOM event can be fired p232 , depending on the current state of
playback.
p230
or less, and the new ready state is
↪ If the previous ready state was HAVE_CURRENT_DATA
p230
HAVE_FUTURE_DATA
The user agent must queue a task p490 to fire a simple event p496 named canplay p237 .
If the element is potentially playing p231 , the user agent must queue a task p490 to fire a simple event p496
named playing p237 .
p230
↪ If the new ready state is HAVE_ENOUGH_DATA
If the previous ready state was HAVE_CURRENT_DATA p230 or less, the user agent must queue a task p490 to
fire a simple event p496 named canplay p237 , and, if the element is also potentially playing p231 , queue a
task p490 to fire a simple event p496 named playing p237 .
If the autoplaying flag p222 is true, and the paused p231 attribute is true, and the media element p219 has an
autoplay p231 attribute specified, and the media element p219 is in a Document p31 whose browsing
context p439 did not have the sandboxed automatic features browsing context flag p203 set when the
Document p31 was created, then the user agent may also set the paused p231 attribute to false, queue a
task p490 to fire a simple event p496 named play p237 , and queue a task p490 to fire a simple event p496 named
playing p237 .
Note: User agents are not required to autoplay, and it is suggested that user agents
honor user preferences on the matter. Authors are urged to use the autoplay p231
attribute rather than using script to force the video to play, so as to allow the user to
override the behavior if so desired.
In any case, the user agent must finally queue a task p490 to fire a simple event p496 named
canplaythrough p237 .
230
Note: It is possible for the ready state of a media element to jump between these states
discontinuously. For example, the state of a media element can jump straight from
HAVE_METADATA p229 to HAVE_ENOUGH_DATA p230 without passing through the HAVE_CURRENT_DATA p230 and
HAVE_FUTURE_DATA p230 states.
The readyState IDL attribute must, on getting, return the value described above that describes the current ready
state of the media element p219 .
The autoplay attribute is a boolean attribute p34 . When present, the user agent (as described in the algorithm
described herein) will automatically begin playback of the media resource p219 as soon as it can do so without
stopping.
Note: Authors are urged to use the autoplay p231 attribute rather than using script to trigger
automatic playback, as this allows the user to override the automatic playback when it is not
desired, e.g. when using a screen reader. Authors are also encouraged to consider not using
the automatic playback behavior at all, and instead to let the user agent wait for the user to
start playback explicitly.
The autoplay IDL attribute must reflect p57 the content attribute of the same name.
4.8.9.8 Playing the media resource
This box is non-normative. Implementation requirements are given below this box.
media . paused p231
Returns true if playback is paused; false otherwise.
media . ended p232
Returns true if playback has reached the end of the media resource p219 .
media . defaultPlaybackRate p232 [ = value ]
Returns the default rate of playback, for when the user is not fast-forwarding or reversing through the
media resource p219 .
Can be set, to change the default rate of playback.
The default rate has no direct effect on playback, but if the user switches to a fast-forward mode,
when they return to the normal playback mode, it is expected that the rate of playback will be
returned to the default rate of playback.
media . playbackRate p232 [ = value ]
Returns the current rate playback, where 1.0 is normal speed.
Can be set, to change the rate of playback.
media . played p232
Returns a TimeRanges p236 object that represents the ranges of the media resource p219 that the user
agent has played.
media . play p232 ()
Sets the paused p231 attribute to false, loading the media resource p219 and beginning playback if
necessary. If the playback had ended, will restart it from the start.
media . pause p233 ()
Sets the paused p231 attribute to true, loading the media resource p219 if necessary.
The paused attribute represents whether the media element p219 is paused or not. The attribute must initially be
true.
A media element p219 is said to be potentially playing when its paused p231 attribute is false, the readyState p231
attribute is either HAVE_FUTURE_DATA p230 or HAVE_ENOUGH_DATA p230 , the element has not ended playback p231 ,
playback has not stopped due to errors p232 , and the element has not paused for user interaction p232 .
A media element p219 is said to have ended playback when the element's readyState p231 attribute is
HAVE_METADATA p229 or greater, and either the current playback position p229 is the end of the media resource p219 and
the direction of playback p232 is forwards and the media element p219 does not have a loop p229 attribute specified, or
the current playback position p229 is the earliest possible position p229 and the direction of playback p232 is backwards.
231
The ended attribute must return true if the media element p219 has ended playback p231 and the direction of
playback p232 is forwards, and false otherwise.
A media element p219 is said to have stopped due to errors when the element's readyState p231 attribute is
HAVE_METADATA p229 or greater, and the user agent encounters a non-fatal error p227 during the processing of the
media data p219 , and due to that error, is not able to play the content at the current playback position p229 .
A media element p219 is said to have paused for user interaction when its paused p231 attribute is false, the
readyState p231 attribute is either HAVE_FUTURE_DATA p230 or HAVE_ENOUGH_DATA p230 and the user agent has reached
a point in the media resource p219 where the user has to make a selection for the resource to continue.
It is possible for a media element p219 to have both ended playback p231 and paused for user interaction p232 at the
same time.
When a media element p219 that is potentially playing p231 stops playing because it has paused for user
interaction p232 , the user agent must queue a task p490 to fire a simple event p496 named timeupdate p237 at the
element.
When a media element p219 that is potentially playing p231 stops playing because its readyState p231 attribute
changes to a value lower than HAVE_FUTURE_DATA p230 , without the element having ended playback p231 , or playback
having stopped due to errors p232 , or playback having paused for user interaction p232 , or the seeking algorithm p234
being invoked, the user agent must queue a task p490 to fire a simple event p496 named timeupdate p237 at the
element, and queue a task p490 to fire a simple event p496 named waiting p237 at the element.
When the current playback position p229 reaches the end of the media resource p219 when the direction of
playback p232 is forwards, then the user agent must follow these steps:
1.
If the media element p219 has a loop p229 attribute specified, then seek p234 to the earliest possible
position p229 of the media resource p219 and abort these steps.
2.
Stop playback.
Note: The ended p232 attribute becomes true.
3.
The user agent must queue a task p490 to fire a simple event p496 named timeupdate p237 at the element.
4.
The user agent must queue a task p490 to fire a simple event p496 named ended p238 at the element.
When the current playback position p229 reaches the earliest possible position p229 of the media resource p219 when
the direction of playback p232 is backwards, then the user agent must follow these steps:
1.
Stop playback.
2.
The user agent must queue a task p490 to fire a simple event p496 named timeupdate p237 at the element.
The defaultPlaybackRate attribute gives the desired speed at which the media resource p219 is to play, as a
multiple of its intrinsic speed. The attribute is mutable: on getting it must return the last value it was set to, or 1.0
if it hasn't yet been set; on setting the attribute must be set to the new value.
The playbackRate attribute gives the speed at which the media resource p219 plays, as a multiple of its intrinsic
speed. If it is not equal to the defaultPlaybackRate p232 , then the implication is that the user is using a feature
such as fast forward or slow motion playback. The attribute is mutable: on getting it must return the last value it
was set to, or 1.0 if it hasn't yet been set; on setting the attribute must be set to the new value, and the playback
must change speed (if the element is potentially playing p231 ).
If the playbackRate p232 is positive or zero, then the direction of playback is forwards. Otherwise, it is
backwards.
The "play" function in a user agent's interface must set the playbackRate p232 attribute to the value of the
defaultPlaybackRate p232 attribute before invoking the play() p232 method's steps. Features such as fast-forward
or rewind must be implemented by only changing the playbackRate p232 attribute.
When the defaultPlaybackRate p232 or playbackRate p232 attributes change value (either by being set by script or
by being changed directly by the user agent, e.g. in response to user control) the user agent must queue a
task p490 to fire a simple event p496 named ratechange p238 at the media element p219 .
The played attribute must return a new static normalized TimeRanges object p236 that represents the ranges of the
media resource p219 , if any, that the user agent has so far rendered, at the time the attribute is evaluated.
When the play() method on a media element p219 is invoked, the user agent must run the following steps.
1.
232
If the media element p219 's networkState p222 attribute has the value NETWORK_EMPTY p222 , invoke the
media element p219 's resource selection algorithm p223 .
2.
If the playback has ended p231 and the direction of playback p232 is forwards, seek p234 to the earliest
possible position p229 of the media resource p219 .
Note: This will cause p234 the user agent to queue a task p490 to fire a simple event p496
named timeupdate p237 at the media element p219 .
3.
4.
If the media element p219 's paused p231 attribute is true, run the following substeps:
1.
Change the value of paused p231 to false.
2.
Queue a task p490 to fire a simple event p496 named play p237 at the element.
3.
If the media element p219 's readyState p231 attribute has the value HAVE_NOTHING p229 ,
HAVE_METADATA p229 , or HAVE_CURRENT_DATA p230 , queue a task p490 to fire a simple event p496
named waiting p237 at the element.
4.
Otherwise, the media element p219 's readyState p231 attribute has the value
HAVE_FUTURE_DATA p230 or HAVE_ENOUGH_DATA p230 ; queue a task p490 to fire a simple event p496
named playing p237 at the element.
Set the media element p219 's autoplaying flag p222 to false.
When the pause() method is invoked, the user agent must run the following steps:
1.
If the media element p219 's networkState p222 attribute has the value NETWORK_EMPTY p222 , invoke the
media element p219 's resource selection algorithm p223 .
2.
Set the media element p219 's autoplaying flag p222 to false.
3.
If the media element p219 's paused p231 attribute is false, run the following steps:
1.
Change the value of paused p231 to true.
2.
Queue a task p490 to fire a simple event p496 named timeupdate p237 at the element.
3.
Queue a task p490 to fire a simple event p496 named pause p237 at the element.
When a media element p219 is potentially playing p231 and its Document p31 is a fully active p440 Document p31 , its current
playback position p229 must increase monotonically at playbackRate p232 units of media time per unit time of wall
clock time.
Note: This specification doesn't define how the user agent achieves the appropriate playback
rate — depending on the protocol and media available, it is plausible that the user agent could
negotiate with the server to have the server provide the media data at the appropriate rate,
so that (except for the period between when the rate is changed and when the server updates
the stream's playback rate) the client doesn't actually have to drop or interpolate any frames.
When the playbackRate p232 is negative (playback is backwards), any corresponding audio must be muted. When
the playbackRate p232 is so low or so high that the user agent cannot play audio usefully, the corresponding audio
must also be muted. If the playbackRate p232 is not 1.0, the user agent may apply pitch adjustments to the audio
as necessary to render it faithfully.
The playbackRate p232 can be 0.0, in which case the current playback position p229 doesn't move, despite playback
not being paused (paused p231 doesn't become true, and the pause p237 event doesn't fire).
Media elements p219 that are potentially playing p231 while not in a Document p27 must not play any video, but should
play any audio component. Media elements must not stop playing just because all references to them have been
removed; only once a media element to which no references exist has reached a point where no further audio
remains to be played for that element (e.g. because the element is paused, or because the end of the clip has
been reached, or because its playbackRate p232 is 0.0) may the element be garbage collected.
When the current playback position p229 of a media element p219 changes (e.g. due to playback or seeking), the user
agent must run the following steps. If the current playback position p229 changes while the steps are running, then
the user agent must wait for the steps to complete, and then must immediately rerun the steps. (These steps are
thus run as often as possible or needed — if one iteration takes a long time, this can cause certain ranges to be
skipped over as the user agent rushes ahead to "catch up".)
1.
If the time was reached through the usual monotonic increase of the current playback position during
normal playback, and if the user agent has not fired a timeupdate p237 event at the element in the past
15 to 250ms and is not still running event handlers for such an event, then the user agent must queue a
233
task p490 to fire a simple event p496 named timeupdate p237 at the element. (In the other cases, such as
explicit seeks, relevant events get fired as part of the overall process of changing the current playback
position.)
Note: The event thus is not to be fired faster than about 66Hz or slower than 4Hz
(assuming the event handlers don't take longer than 250ms to run). User agents are
encouraged to vary the frequency of the event based on the system load and the
average cost of processing the event each time, so that the UI updates are not any
more frequent than the user agent can comfortably handle while decoding the video.
When a media element p219 is removed from a Document p27 , if the media element p219 's networkState p222 attribute
has a value other than NETWORK_EMPTY p222 then the user agent must act as if the pause() p233 method had been
invoked.
Note: If the media element p219 's Document p31 stops being a fully active p440 document, then the
playback will stop p233 until the document is active again.
4.8.9.9 Seeking
This box is non-normative. Implementation requirements are given below this box.
media . seeking
p234
Returns true if the user agent is currently seeking.
media . seekable p235
Returns a TimeRanges p236 object that represents the ranges of the media resource p219 to which it is
possible for the user agent to seek.
The seeking attribute must initially have the value false.
When the user agent is required to seek to a particular new playback position in the media resource p219 , it means
that the user agent must run the following steps. This algorithm interacts closely with the event loop p489
mechanism; in particular, it has a synchronous section p490 (which is triggered as part of the event loop p489
algorithm). Steps in that section are marked with ?.
1.
If the media element p219 's readyState p231 is HAVE_NOTHING p229 , then raise an INVALID_STATE_ERR p70
exception (if the seek was in response to a DOM method call or setting of an IDL attribute), and abort
these steps.
2.
If the element's seeking p234 IDL attribute is true, then another instance of this algorithm is already
running. Abort that other instance of the algorithm without waiting for the step that it is running to
complete.
3.
Set the seeking p234 IDL attribute to true.
4.
Queue a task p490 to fire a simple event p496 named timeupdate p237 at the element.
5.
If the seek was in response to a DOM method call or setting of an IDL attribute, then continue the script.
The remainder of these steps must be run asynchronously. With the exception of the steps marked with
?, they could be aborted at any time by another instance of this algorithm being invoked.
6.
If the new playback position is later than the end of the media resource p219 , then let it be the end of the
media resource p219 instead.
7.
If the new playback position is less than the earliest possible position p229 , let it be that position instead.
8.
If the (possibly now changed) new playback position is not in one of the ranges given in the seekable p235
attribute, then let it be the position in one of the ranges given in the seekable p235 attribute that is the
nearest to the new playback position. If two positions both satisfy that constraint (i.e. the new playback
position is exactly in the middle between two ranges in the seekable p235 attribute) then use the position
that is closest to the current playback position p229 . If there are no ranges given in the seekable p235
attribute then set the seeking p234 IDL attribute to false and abort these steps.
9.
Set the current playback position p229 to the given new playback position.
10.
234
If the media element p219 was potentially playing p231 immediately before it started seeking, but seeking
caused its readyState p231 attribute to change to a value lower than HAVE_FUTURE_DATA p230 , then queue
a task p490 to fire a simple event p496 named waiting p237 at the element.
11.
If, when it reaches this step, the user agent has still not established whether or not the media data p219
for the new playback position is available, and, if it is, decoded enough data to play back that position,
then queue a task p490 to fire a simple event p496 named seeking p237 at the element.
12.
Wait until it has established whether or not the media data p219 for the new playback position is available,
and, if it is, until it has decoded enough data to play back that position.
13.
Await a stable state p490 . The synchronous section p490 consists of all the remaining steps of this algorithm.
(Steps in the synchronous section p490 are marked with ?.)
14.
? Set the seeking p234 IDL attribute to false.
15.
? Queue a task p490 to fire a simple event p496 named seeked p237 at the element.
The seekable attribute must return a new static normalized TimeRanges object p236 that represents the ranges of
the media resource p219 , if any, that the user agent is able to seek to, at the time the attribute is evaluated.
Note: If the user agent can seek to anywhere in the media resource p219 , e.g. because it a
simple movie file and the user agent and the server support HTTP Range requests, then the
attribute would return an object with one range, whose start is the time of the first frame
(typically zero), and whose end is the same as the time of the first frame plus the duration p228
attribute's value (which would equal the time of the last frame).
Note: The range might be continuously changing, e.g. if the user agent is buffering a sliding
window on an infinite stream. This is the behavior seen with DVRs viewing live TV, for
instance.
Media resources p219 might be internally scripted or interactive. Thus, a media element p219 could play in a nonlinear fashion. If this happens, the user agent must act as if the algorithm for seeking p234 was used whenever the
current playback position p229 changes in a discontinuous fashion (so that the relevant events fire).
4.8.9.10 User interface
The controls attribute is a boolean attribute p34 . If present, it indicates that the author has not provided a scripted
controller and would like the user agent to provide its own set of controls.
If the attribute is present, or if scripting is disabled p487 for the media element p219 , then the user agent should
expose a user interface to the user. This user interface should include features to begin playback, pause
playback, seek to an arbitrary position in the content (if the content supports arbitrary seeking), change the
volume, change the display of closed captions or embedded sign-language tracks, select different audio tracks or
turn on audio descriptions, and show the media content in manners more suitable to the user (e.g. full-screen
video or in an independent resizable window). Other controls may also be made available.
Even when the attribute is absent, however, user agents may provide controls to affect playback of the media
resource (e.g. play, pause, seeking, and volume controls), but such features should not interfere with the page's
normal rendering. For example, such features could be exposed in the media element p219 's context menu.
Where possible (specifically, for starting, stopping, pausing, and unpausing playback, for muting or changing the
volume of the audio, and for seeking), user interface features exposed by the user agent must be implemented in
terms of the DOM API described above, so that, e.g., all the same events fire.
The controls IDL attribute must reflect p57 the content attribute of the same name.
This box is non-normative. Implementation requirements are given below this box.
media . volume
p236
[ = value ]
Returns the current playback volume, as a number in the range 0.0 to 1.0, where 0.0 is the quietest
and 1.0 the loudest.
Can be set, to change the volume.
Throws an INDEX_SIZE_ERR p70 if the new value is not in the range 0.0 .. 1.0.
media . muted p236 [ = value ]
Returns true if audio is muted, overriding the volume p236 attribute, and false if the volume p236 attribute
is being honored.
Can be set, to change whether the audio is muted or not.
235
The volume attribute must return the playback volume of any audio portions of the media element p219 , in the
range 0.0 (silent) to 1.0 (loudest). Initially, the volume must be 1.0, but user agents may remember the last set
value across sessions, on a per-site basis or otherwise, so the volume may start at other values. On setting, if the
new value is in the range 0.0 to 1.0 inclusive, the attribute must be set to the new value and the playback volume
must be correspondingly adjusted as soon as possible after setting the attribute, with 0.0 being silent, and 1.0
being the loudest setting, values in between increasing in loudness. The range need not be linear. The loudest
setting may be lower than the system's loudest possible setting; for example the user could have set a maximum
volume. If the new value is outside the range 0.0 to 1.0 inclusive, then, on setting, an INDEX_SIZE_ERR p70
exception must be raised instead.
The muted attribute must return true if the audio channels are muted and false otherwise. Initially, the audio
channels should not be muted (false), but user agents may remember the last set value across sessions, on a persite basis or otherwise, so the muted state may start as muted (true). On setting, the attribute must be set to the
new value; if the new value is true, audio playback for this media resource p219 must then be muted, and if false,
audio playback must then be enabled.
Whenever either the muted p236 or volume p236 attributes are changed, the user agent must queue a task p490 to fire a
simple event p496 named volumechange p238 at the media element p219 .
4.8.9.11 Time ranges
Objects implementing the TimeRanges p236 interface represent a list of ranges (periods) of time.
interface TimeRanges {
readonly attribute unsigned long length;
float start(in unsigned long index);
float end(in unsigned long index);
};
This box is non-normative. Implementation requirements are given below this box.
media . length
p236
Returns the number of ranges in the object.
time = media . start p236 (index)
Returns the time for the start of the range with the given index.
Throws an INDEX_SIZE_ERR p70 if the index is out of range.
time = media . end p236 (index)
Returns the time for the end of the range with the given index.
Throws an INDEX_SIZE_ERR p70 if the index is out of range.
The length IDL attribute must return the number of ranges represented by the object.
The start(index) method must return the position of the start of the indexth range represented by the object, in
seconds measured from the start of the timeline that the object covers.
The end(index) method must return the position of the end of the indexth range represented by the object, in
seconds measured from the start of the timeline that the object covers.
These methods must raise INDEX_SIZE_ERR p70 exceptions if called with an index argument greater than or equal
to the number of ranges represented by the object.
When a TimeRanges p236 object is said to be a normalized TimeRanges object, the ranges it represents must obey
the following criteria:
•
The start of a range must be greater than the end of all earlier ranges.
•
The start of a range must be less than the end of that same range.
In other words, the ranges in such an object are ordered, don't overlap, aren't empty, and don't touch (adjacent
ranges are folded into one bigger range).
The timelines used by the objects returned by the buffered p228 , seekable p235 and played p232 IDL attributes of
media elements p219 must be the same as that element's media resource p219 's timeline.
236
4.8.9.12 Event summary
This section is non-normative.
The following events fire on media elements p219 as part of the processing model described above:
Event name
Interface
Dispatched when...
Preconditions
loadstart
Event p31
The user agent begins looking for media
data p219 , as part of the resource selection
algorithm p223 .
networkState p222 equals NETWORK_LOADING p222
progress
Event p31
The user agent is fetching media data p219 .
networkState p222 equals NETWORK_LOADING p222
The user agent is intentionally not currently
fetching media data p219 , but does not have
the entire media resource p219 downloaded.
networkState p222 equals NETWORK_IDLE p222
p31
suspend
Event
abort
Event p31
The user agent stops fetching the media
data p219 before it is completely downloaded,
but not due to an error.
error p220 is an object with the code MEDIA_ERR_ABORTED p220 .
networkState p222 equals either NETWORK_EMPTY p222 or
NETWORK_IDLE p222 , depending on when the download was
aborted.
error
Event p31
An error occurs while fetching the media
data p219 .
error p220 is an object with the code MEDIA_ERR_NETWORK p220
or higher. networkState p222 equals either
NETWORK_EMPTY p222 or NETWORK_IDLE p222 , depending on
when the download was aborted.
emptied
Event p31
A media element p219 whose networkState p222 networkState p222 is NETWORK_EMPTY p222 ; all the IDL
was previously not in the NETWORK_EMPTY p222 attributes are in their initial states.
state has just switched to that state (either
because of a fatal error during load that's
about to be reported, or because the
load() p222 method was invoked while the
resource selection algorithm p223 was already
running).
stalled
Event p31
The user agent is trying to fetch media
data p219 , but data is unexpectedly not
forthcoming.
networkState p222 is NETWORK_LOADING p222 .
play
Event p31
Playback has begun. Fired after the
play() p232 method has returned.
paused p231 is newly false.
pause
Event p31
Playback has been paused. Fired after the
pause p233 method has returned.
paused p231 is newly true.
The user agent has just determined the
duration and dimensions of the media
resource p219 .
readyState p231 is newly equal to HAVE_METADATA p229 or
greater for the first time.
loadedmetadata Event p31
loadeddata
Event p31
The user agent can render the media data p219 readyState p231 newly increased to HAVE_CURRENT_DATA p230
or greater for the first time.
at the current playback position p229 for the
first time.
waiting
Event p31
Playback has stopped because the next
frame is not available, but the user agent
expects that frame to become available in
due course.
readyState p231 is newly equal to or less than
HAVE_CURRENT_DATA p230 , and paused p231 is false. Either
seeking p234 is true, or the current playback position p229 is
not contained in any of the ranges in buffered p228 . It is
possible for playback to stop for two other reasons without
paused p231 being false, but those two reasons do not fire this
event: maybe playback ended p231 , or playback stopped due
to errors p232 .
playing
Event p31
Playback has started.
readyState p231 is newly equal to or greater than
HAVE_FUTURE_DATA p230 , paused p231 is false, seeking p234 is
false, or the current playback position p229 is contained in
one of the ranges in buffered p228 .
canplay
Event p31
The user agent can resume playback of the
media data p219 , but estimates that if
playback were to be started now, the media
resource p219 could not be rendered at the
current playback rate up to its end without
having to stop for further buffering of
content.
readyState p231 newly increased to HAVE_FUTURE_DATA p230 or
greater.
canplaythrough Event p31
The user agent estimates that if playback
readyState p231 is newly equal to HAVE_ENOUGH_DATA p230 .
were to be started now, the media
resource p219 could be rendered at the current
playback rate all the way to its end without
having to stop for further buffering.
seeking
Event p31
The seeking p234 IDL attribute changed to true
and the seek operation is taking long enough
that the user agent has time to fire the
event.
seeked
Event p31
The seeking p234 IDL attribute changed to
false.
timeupdate
Event p31
The current playback position p229 changed as
part of normal playback or in an especially
interesting way, for example discontinuously.
237
Event name
Interface
Dispatched when...
Preconditions
ended
Event p31
Playback has stopped because the end of the currentTime p229 equals the end of the media resource p219 ;
media resource p219 was reached.
ended p232 is true.
ratechange
Event p31
Either the defaultPlaybackRate p232 or the
playbackRate p232 attribute has just been
updated.
durationchange Event p31
Event p31
volumechange
The duration p228 attribute has just been
updated.
Either the volume p236 attribute or the
muted p236 attribute has changed. Fired after
the relevant attribute's setter has returned.
4.8.9.13 Security and privacy considerations
The main security and privacy implications of the video p213 and audio p216 elements come from the ability to
embed media cross-origin. There are two directions that threats can flow: from hostile content to a victim page,
and from a hostile page to victim content.
If a victim page embeds hostile content, the threat is that the content might contain scripted code that attempts
to interact with the Document p31 that embeds the content. To avoid this, user agents must ensure that there is no
access from the content to the embedding page. In the case of media content that uses DOM concepts, the
embedded content must be treated as if it was in its own unrelated top-level browsing context p439 .
For instance, if an SVG animation was embedded in a video p213 element, the user agent would not give it
access to the DOM of the outer page. From the perspective of scripts in the SVG resource, the SVG file
would appear to be in a lone top-level browsing context with no parent.
If a hostile page embeds victim content, the threat is that the embedding page could obtain information from the
content that it would not otherwise have access to. The API does expose some information: the existence of the
media, its type, its duration, its size, and the performance characteristics of its host. Such information is already
potentially problematic, but in practice the same information can more or less be obtained using the img p186
element, and so it has been deemed acceptable.
However, significantly more sensitive information could be obtained if the user agent further exposes metadata
within the content such as subtitles or chapter titles. This version of the API does not expose such information.
Future extensions to this API will likely reuse a mechanism such as CORS to check that the embedded content's
site has opted in to exposing such information. [CORS] p700
An attacker could trick a user running within a corporate network into visiting a site that attempts to load a
video from a previously leaked location on the corporation's intranet. If such a video included confidential
plans for a new product, then being able to read the subtitles would present a confidentiality breach.
4.8.10 The canvas element
Categories
Flow content p91 .
Phrasing content p91 .
Embedded content p92 .
Contexts in which this element may be used:
Where embedded content p92 is expected.
Content model:
Transparent p93 .
Content attributes:
Global attributes p82
width p239
height p239
DOM interface:
interface HTMLCanvasElement : HTMLElement {
attribute unsigned long width;
attribute unsigned long height;
DOMString toDataURL(in optional DOMString type, in any... args);
238
object getContext(in DOMString contextId);
};
The canvas p238 element provides scripts with a resolution-dependent bitmap canvas, which can be used for
rendering graphs, game graphics, or other visual images on the fly.
Authors should not use the canvas p238 element in a document when a more suitable element is available. For
example, it is inappropriate to use a canvas p238 element to render a page heading: if the desired presentation of
the heading is graphically intense, it should be marked up using appropriate elements (typically h1 p139 ) and then
styled using CSS and supporting technologies such as XBL.
When authors use the canvas p238 element, they must also provide content that, when presented to the user,
conveys essentially the same function or purpose as the bitmap canvas. This content may be placed as content of
the canvas p238 element. The contents of the canvas p238 element, if any, are the element's fallback content p92 .
In interactive visual media, if scripting is enabled p487 for the canvas p238 element, and if support for canvas p238
elements has been enabled, the canvas p238 element represents p638 embedded content p92 consisting of a
dynamically created image.
In non-interactive, static, visual media, if the canvas p238 element has been previously painted on (e.g. if the page
was viewed in an interactive visual medium and is now being printed, or if some script that ran during the page
layout process painted on the element), then the canvas p238 element represents p638 embedded content p92 with the
current image and size. Otherwise, the element represents its fallback content p92 instead.
In non-visual media, and in visual media if scripting is disabled p487 for the canvas p238 element or if support for
canvas p238 elements has been disabled, the canvas p238 element represents p638 its fallback content p92 instead.
When a canvas p238 element represents p638 embedded content p92 , the user can still focus descendants of the
canvas p238 element (in the fallback content p92 ). This allows authors to make an interactive canvas keyboardfocusable: authors should have a one-to-one mapping of interactive regions to focusable elements in the fallback
content p92 .
The canvas p238 element has two attributes to control the size of the coordinate space: width and height. These
attributes, when specified, must have values that are valid non-negative integers p35 . The rules for parsing nonnegative integers p35 must be used to obtain their numeric values. If an attribute is missing, or if parsing its value
returns an error, then the default value must be used instead. The width p239 attribute defaults to 300, and the
height p239 attribute defaults to 150.
The intrinsic dimensions of the canvas p238 element equal the size of the coordinate space, with the numbers
interpreted in CSS pixels. However, the element can be sized arbitrarily by a style sheet. During rendering, the
image is scaled to fit this layout size.
The size of the coordinate space does not necessarily represent the size of the actual bitmap that the user agent
will use internally or during rendering. On high-definition displays, for instance, the user agent may internally use
a bitmap with two device pixels per unit in the coordinate space, so that the rendering remains at high quality
throughout.
When the canvas p238 element is created, and subsequently whenever the width p239 and height p239 attributes are
set (whether to a new value or to the previous value), the bitmap and any associated contexts must be cleared
back to their initial state and reinitialized with the newly specified coordinate space dimensions.
When the canvas is initialized, its bitmap must be cleared to transparent black.
The width and height IDL attributes must reflect p57 the respective content attributes of the same name.
Only one square appears to be drawn in the following example:
// canvas is a reference to a element
var context = canvas.getContext('2d');
context.fillRect(0,0,50,50);
canvas.setAttribute('width', '300'); // clears the canvas
context.fillRect(0,100,50,50);
canvas.width = canvas.width; // clears the canvas
context.fillRect(100,0,50,50); // only this square remains
To draw on the canvas, authors must first obtain a reference to a context using the getContext(contextId)
method of the canvas p238 element.
This box is non-normative. Implementation requirements are given below this box.
239
context = canvas . getContext p239 (contextId)
Returns an object that exposes an API for drawing on the canvas.
Returns null if the given context ID is not supported.
This specification only defines one context, with the name "2d p241 ". If getContext() p239 is called with that exact
string for its contextId argument, then the UA must return a reference to an object implementing
CanvasRenderingContext2D p241 . Other specifications may define their own contexts, which would return different
objects.
Vendors may also define experimental contexts using the syntax vendorname-context, for example, moz-3d.
When the UA is passed an empty string or a string specifying a context that it does not support, then it must
return null. String comparisons must be case-sensitive p33 .
This box is non-normative. Implementation requirements are given below this box.
url = canvas . toDataURL p240 ( [ type, ... ])
Returns a data: URL for the image in the canvas.
The first argument, if provided, controls the type of the image to be returned (e.g. PNG or JPEG). The
default is image/png; that type is also used if the given type isn't supported. The other arguments are
specific to the type, and control the way that the image is generated, as given in the table below.
The toDataURL() method must, when called with no arguments, return a data: URL containing a representation
of the image as a PNG file. [PNG] p702
If the canvas has no pixels (i.e. either its horizontal dimension or its vertical dimension is zero) then the method
must return the string "data:,". (This is the shortest data: URL; it represents the empty string in a text/plain
resource.)
When the toDataURL(type) p240 method is called with one or more arguments, it must return a data: URL
containing a representation of the image in the format given by type. The possible values are MIME types p26 with
no parameters, for example image/png, image/jpeg, or even maybe image/svg+xml if the implementation
actually keeps enough information to reliably render an SVG image from the canvas.
For image types that do not support an alpha channel, the image must be composited onto a solid black
background using the source-over operator, and the resulting image must be the one used to create the data:
URL.
Only support for image/png is required. User agents may support other types. If the user agent does not support
the requested type, it must return the image using the PNG format.
User agents must convert the provided type to ASCII lowercase p33 before establishing if they support that type and
before creating the data: URL.
Note: When trying to use types other than image/png, authors can check if the image was
really returned in the requested format by checking to see if the returned string starts with
one the exact strings "data:image/png," or "data:image/png;". If it does, the image is PNG, and
thus the requested type was not supported. (The one exception to this is if the canvas has
either no height or no width, in which case the result might simply be "data:,".)
If the method is invoked with the first argument giving a type corresponding to one of the types given in the first
column of the following table, and the user agent supports that type, then the subsequent arguments, if any, must
be treated as described in the second cell of that row.
Type
Other arguments
image/ The second argument, if it is a number in the range 0.0 to 1.0 inclusive, must be treated as the desired quality level. If it is not a
jpeg
number or is outside that range, the user agent must use its default value, as if the argument had been omitted.
For the purposes of these rules, an argument is considered to be a number if it is converted to an IDL double value
by the rules for handling arguments of type any in the Web IDL specification. [WEBIDL] p704
Other arguments must be ignored and must not cause the user agent to raise an exception. A future version of
this specification will probably define other parameters to be passed to toDataURL() p240 to allow authors to more
carefully control compression settings, image metadata, etc.
240
4.8.10.1 The 2D context
When the getContext() p239 method of a canvas p238 element is invoked with 2d as the argument, a
CanvasRenderingContext2D p241 object is returned.
There is only one CanvasRenderingContext2D p241 object per canvas, so calling the getContext() p239 method with
the 2d p241 argument a second time must return the same object.
The 2D context represents a flat Cartesian surface whose origin (0,0) is at the top left corner, with the coordinate
space having x values increasing when going right, and y values increasing when going down.
interface CanvasRenderingContext2D {
// back-reference to the canvas
readonly attribute HTMLCanvasElement canvas;
// state
void save(); // push state on state stack
void restore(); // pop state stack and restore state
// transformations (default transform is the identity matrix)
void scale(in float x, in float y);
void rotate(in float angle);
void translate(in float x, in float y);
void transform(in float m11, in float m12, in float m21, in float m22, in float dx, in
float dy);
void setTransform(in float m11, in float m12, in float m21, in float m22, in float dx,
in float dy);
// compositing
attribute float globalAlpha; // (default 1.0)
attribute DOMString globalCompositeOperation; // (default source-over)
// colors and styles
attribute any strokeStyle; // (default black)
attribute any fillStyle; // (default black)
CanvasGradient createLinearGradient(in float x0, in float y0, in float x1, in float
y1);
CanvasGradient createRadialGradient(in float x0, in float y0, in float r0, in float
x1, in float y1, in float r1);
CanvasPattern createPattern(in HTMLImageElement image, in DOMString repetition);
CanvasPattern createPattern(in HTMLCanvasElement image, in DOMString repetition);
CanvasPattern createPattern(in HTMLVideoElement image, in DOMString repetition);
// line caps/joins
attribute
attribute
attribute
attribute
float lineWidth; // (default 1)
DOMString lineCap; // "butt", "round", "square" (default "butt")
DOMString lineJoin; // "round", "bevel", "miter" (default "miter")
float miterLimit; // (default 10)
// shadows
attribute
attribute
attribute
attribute
float shadowOffsetX; // (default 0)
float shadowOffsetY; // (default 0)
float shadowBlur; // (default 0)
DOMString shadowColor; // (default transparent black)
// rects
void clearRect(in float x, in float y, in float w, in float h);
void fillRect(in float x, in float y, in float w, in float h);
void strokeRect(in float x, in float y, in float w, in float h);
// path API
void beginPath();
void closePath();
void moveTo(in float x, in float y);
void lineTo(in float x, in float y);
void quadraticCurveTo(in float cpx, in float cpy, in float x, in float y);
void bezierCurveTo(in float cp1x, in float cp1y, in float cp2x, in float cp2y, in
float x, in float y);
241
void arcTo(in float x1, in float y1, in float x2, in float y2, in float radius);
void rect(in float x, in float y, in float w, in float h);
void arc(in float x, in float y, in float radius, in float startAngle, in float
endAngle, in boolean anticlockwise);
void fill();
void stroke();
void clip();
boolean isPointInPath(in float x, in float y);
// focus management
boolean drawFocusRing(in Element element, in float xCaret, in float yCaret, in
optional boolean canDrawCustom);
// text
attribute DOMString font; // (default 10px sans-serif)
attribute DOMString textAlign; // "start", "end", "left", "right", "center"
(default: "start")
attribute DOMString textBaseline; // "top", "hanging", "middle",
"alphabetic", "ideographic", "bottom" (default: "alphabetic")
void fillText(in DOMString text, in float x, in float y, in optional float maxWidth);
void strokeText(in DOMString text, in float x, in float y, in optional float maxWidth);
TextMetrics measureText(in DOMString text);
// drawing images
void drawImage(in HTMLImageElement image, in float dx, in float dy, in optional float
dw, in float dh);
void drawImage(in HTMLImageElement image, in float sx, in float sy, in float sw, in
float sh, in float dx, in float dy, in float dw, in float dh);
void drawImage(in HTMLCanvasElement image, in float dx, in float dy, in optional float
dw, in float dh);
void drawImage(in HTMLCanvasElement image, in float sx, in float sy, in float sw, in
float sh, in float dx, in float dy, in float dw, in float dh);
void drawImage(in HTMLVideoElement image, in float dx, in float dy, in optional float
dw, in float dh);
void drawImage(in HTMLVideoElement image, in float sx, in float sy, in float sw, in
float sh, in float dx, in float dy, in float dw, in float dh);
// pixel manipulation
ImageData createImageData(in float sw, in float sh);
ImageData createImageData(in ImageData imagedata);
ImageData getImageData(in float sx, in float sy, in float sw, in float sh);
void putImageData(in ImageData imagedata, in float dx, in float dy, in optional float
dirtyX, in float dirtyY, in float dirtyWidth, in float dirtyHeight);
};
interface CanvasGradient {
// opaque object
void addColorStop(in float offset, in DOMString color);
};
interface CanvasPattern {
// opaque object
};
interface TextMetrics {
readonly attribute float width;
};
interface ImageData {
readonly attribute unsigned long width;
readonly attribute unsigned long height;
readonly attribute CanvasPixelArray data;
};
interface CanvasPixelArray {
readonly attribute unsigned long length;
getter octet (in unsigned long index);
setter void (in unsigned long index, in octet value);
};
242
This box is non-normative. Implementation requirements are given below this box.
context . canvas
p243
Returns the canvas p238 element.
The canvas attribute must return the canvas p238 element that the context paints on.
Except where otherwise specified, for the 2D context interface, any method call with a numeric argument whose
value is infinite or a NaN value must be ignored.
Whenever the CSS value currentColor is used as a color in this API, the "computed value of the 'color' property"
for the purposes of determining the computed value of the currentColor keyword is the computed value of the
'color' property on the element in question at the time that the color is specified (e.g. when the appropriate
attribute is set, or when the method is called; not when the color is rendered or otherwise used). If the computed
value of the 'color' property is undefined for a particular case (e.g. because the element is not in a Document p27 ),
then the "computed value of the 'color' property" for the purposes of determining the computed value of the
currentColor keyword is fully opaque black. [CSSCOLOR] p700
4.8.10.1.1 The canvas state
Each context maintains a stack of drawing states. Drawing states consist of:
•
•
•
The current transformation matrix p243 .
The current clipping region p253 .
The current values of the following attributes: strokeStyle p245 , fillStyle p245 , globalAlpha p244 ,
lineWidth p248 , lineCap p248 , lineJoin p249 , miterLimit p249 , shadowOffsetX p250 , shadowOffsetY p250 ,
shadowBlur p250 , shadowColor p249 , globalCompositeOperation p244 , font p255 , textAlign p256 ,
textBaseline p256 .
Note: The current path and the current bitmap are not part of the drawing state. The current
path is persistent, and can only be reset using the beginPath() p252 method. The current bitmap
is a property of the canvas, not the context.
This box is non-normative. Implementation requirements are given below this box.
context . save p243 ()
Pushes the current state onto the stack.
context . restore p243 ()
Pops the top state on the stack, restoring the context to that state.
The save() method must push a copy of the current drawing state onto the drawing state stack.
The restore() method must pop the top entry in the drawing state stack, and reset the drawing state it
describes. If there is no saved state, the method must do nothing.
4.8.10.1.2 Transformations
The transformation matrix is applied to coordinates when creating shapes and paths.
When the context is created, the transformation matrix must initially be the identity transform. It may then be
adjusted using the transformation methods.
The transformations must be performed in reverse order. For instance, if a scale transformation that doubles the
width is applied, followed by a rotation transformation that rotates drawing operations by a quarter turn, and a
rectangle twice as wide as it is tall is then drawn on the canvas, the actual result will be a square.
This box is non-normative. Implementation requirements are given below this box.
context . scale
p244
(x, y)
Changes the transformation matrix to apply a scaling transformation with the given characteristics.
context . rotate p244 (angle)
Changes the transformation matrix to apply a rotation transformation with the given characteristics.
The angle is in radians.
243
context . translate p244 (x, y)
Changes the transformation matrix to apply a translation transformation with the given
characteristics.
context . transform p244 (m11, m12, m21, m22, dx, dy)
Changes the transformation matrix to apply the matrix given by the arguments as described below.
context . setTransform p244 (m11, m12, m21, m22, dx, dy)
Changes the transformation matrix to the matrix given by the arguments as described below.
The scale(x, y) method must add the scaling transformation described by the arguments to the transformation
matrix. The x argument represents the scale factor in the horizontal direction and the y argument represents the
scale factor in the vertical direction. The factors are multiples.
The rotate(angle) method must add the rotation transformation described by the argument to the
transformation matrix. The angle argument represents a clockwise rotation angle expressed in radians.
The translate(x, y) method must add the translation transformation described by the arguments to the
transformation matrix. The x argument represents the translation distance in the horizontal direction and the y
argument represents the translation distance in the vertical direction. The arguments are in coordinate space
units.
The transform(m11, m12, m21, m22, dx, dy) method must multiply the current transformation matrix with the
matrix described by:
m11 m21 dx
m12 m22 dy
0
0 1
The setTransform(m11, m12, m21, m22, dx, dy) method must reset the current transform to the identity
matrix, and then invoke the transform p244 (m11, m12, m21, m22, dx, dy) method with the same arguments.
4.8.10.1.3 Compositing
This box is non-normative. Implementation requirements are given below this box.
context . globalAlpha
p244
[ = value ]
Returns the current alpha value applied to rendering operations.
Can be set, to change the alpha value. Values outside of the range 0.0 .. 1.0 are ignored.
context . globalCompositeOperation p244 [ = value ]
Returns the current composition operation, from the list below.
Can be set, to change the composition operation. Unknown values are ignored.
All drawing operations are affected by the global compositing attributes, globalAlpha p244 and
globalCompositeOperation p244 .
The globalAlpha attribute gives an alpha value that is applied to shapes and images before they are composited
onto the canvas. The value must be in the range from 0.0 (fully transparent) to 1.0 (no additional transparency). If
an attempt is made to set the attribute to a value outside this range, including Infinity and Not-a-Number (NaN)
values, the attribute must retain its previous value. When the context is created, the globalAlpha p244 attribute
must initially have the value 1.0.
The globalCompositeOperation attribute sets how shapes and images are drawn onto the existing bitmap, once
they have had globalAlpha p244 and the current transformation matrix applied. It must be set to a value from the
following list. In the descriptions below, the source image, A, is the shape or image being rendered, and the
destination image, B, is the current state of the bitmap.
source-atop
A atop B. Display the source image wherever both images are opaque. Display the destination image
wherever the destination image is opaque but the source image is transparent. Display transparency
elsewhere.
source-in
A in B. Display the source image wherever both the source image and destination image are opaque. Display
transparency elsewhere.
244
source-out
A out B. Display the source image wherever the source image is opaque and the destination image is
transparent. Display transparency elsewhere.
source-over (default)
A over B. Display the source image wherever the source image is opaque. Display the destination image
elsewhere.
destination-atop
B atop A. Same as source-atop p244 but using the destination image instead of the source image and vice
versa.
destination-in
B in A. Same as source-in p244 but using the destination image instead of the source image and vice versa.
destination-out
B out A. Same as source-out p245 but using the destination image instead of the source image and vice
versa.
destination-over
B over A. Same as source-over p245 but using the destination image instead of the source image and vice
versa.
lighter
A plus B. Display the sum of the source image and destination image, with color values approaching 1 as a
limit.
copy
A (B is ignored). Display the source image instead of the destination image.
xor
A xor B. Exclusive OR of the source image and destination image.
vendorName-operationName
Vendor-specific extensions to the list of composition operators should use this syntax.
These values are all case-sensitive — they must be used exactly as shown. User agents must not recognize values
that are not a case-sensitive p33 match for one of the values given above.
The operators in the above list must be treated as described by the Porter-Duff operator given at the start of their
description (e.g. A over B). [PORTERDUFF] p702
On setting, if the user agent does not recognize the specified value, it must be ignored, leaving the value of
globalCompositeOperation p244 unaffected.
When the context is created, the globalCompositeOperation p244 attribute must initially have the value sourceover.
4.8.10.1.4 Colors and styles
This box is non-normative. Implementation requirements are given below this box.
context . strokeStyle p245 [ = value ]
Returns the current style used for stroking shapes.
Can be set, to change the stroke style.
The style can be either a string containing a CSS color, or a CanvasGradient p242 or CanvasPattern p242
object. Invalid values are ignored.
context . fillStyle p245 [ = value ]
Returns the current style used for filling shapes.
Can be set, to change the fill style.
The style can be either a string containing a CSS color, or a CanvasGradient p242 or CanvasPattern p242
object. Invalid values are ignored.
The strokeStyle attribute represents the color or style to use for the lines around shapes, and the fillStyle
attribute represents the color or style to use inside the shapes.
Both attributes can be either strings, CanvasGradient p242 s, or CanvasPattern p242 s. On setting, strings must be
parsed as CSS values and the color assigned, and CanvasGradient p242 and CanvasPattern p242 objects
245
must be assigned themselves. [CSSCOLOR] p700 If the value is a string but is not a valid color, or is neither a string,
a CanvasGradient p242 , nor a CanvasPattern p242 , then it must be ignored, and the attribute must retain its previous
value.
When set to a CanvasPattern p242 or CanvasGradient p242 object, the assignment is live p27 , meaning that changes
made to the object after the assignment do affect subsequent stroking or filling of shapes.
On getting, if the value is a color, then the serialization of the color p246 must be returned. Otherwise, if it is not a
color but a CanvasGradient p242 or CanvasPattern p242 , then the respective object must be returned. (Such objects
are opaque and therefore only useful for assigning to other attributes or for comparison to other gradients or
patterns.)
The serialization of a color for a color value is a string, computed as follows: if it has alpha equal to 1.0, then
the string is a lowercase six-digit hex value, prefixed with a "#" character (U+0023 NUMBER SIGN), with the first
two digits representing the red component, the next two digits representing the green component, and the last
two digits representing the blue component, the digits being in the range 0-9 a-f (U+0030 to U+0039 and U+0061
to U+0066). Otherwise, the color value has alpha less than 1.0, and the string is the color value in the CSS rgba()
functional-notation format: the literal string rgba (U+0072 U+0067 U+0062 U+0061) followed by a U+0028 LEFT
PARENTHESIS, a base-ten integer in the range 0-255 representing the red component (using digits 0-9, U+0030 to
U+0039, in the shortest form possible), a literal U+002C COMMA and U+0020 SPACE, an integer for the green
component, a comma and a space, an integer for the blue component, another comma and space, a U+0030
DIGIT ZERO, a U+002E FULL STOP (representing the decimal point), one or more digits in the range 0-9 (U+0030
to U+0039) representing the fractional part of the alpha value, and finally a U+0029 RIGHT PARENTHESIS.
When the context is created, the strokeStyle p245 and fillStyle p245 attributes must initially have the string value
#000000.
There are two types of gradients, linear gradients and radial gradients, both represented by objects implementing
the opaque CanvasGradient p242 interface.
Once a gradient has been created (see below), stops are placed along it to define how the colors are distributed
along the gradient. The color of the gradient at each stop is the color specified for that stop. Between each such
stop, the colors and the alpha component must be linearly interpolated over the RGBA space without
premultiplying the alpha value to find the color to use at that offset. Before the first stop, the color must be the
color of the first stop. After the last stop, the color must be the color of the last stop. When there are no stops, the
gradient is transparent black.
This box is non-normative. Implementation requirements are given below this box.
gradient . addColorStop p246 (offset, color)
Adds a color stop with the given color to the gradient at the given offset. 0.0 is the offset at one end of
the gradient, 1.0 is the offset at the other end.
Throws an INDEX_SIZE_ERR p70 exception if the offset is out of range. Throws a SYNTAX_ERR p70
exception if the color cannot be parsed.
gradient = context . createLinearGradient p246 (x0, y0, x1, y1)
Returns a CanvasGradient p242 object that represents a linear gradient that paints along the line given
by the coordinates represented by the arguments.
If any of the arguments are not finite numbers, throws a NOT_SUPPORTED_ERR p70 exception.
gradient = context . createRadialGradient p247 (x0, y0, r0, x1, y1, r1)
Returns a CanvasGradient p242 object that represents a radial gradient that paints along the cone given
by the circles represented by the arguments.
If any of the arguments are not finite numbers, throws a NOT_SUPPORTED_ERR p70 exception. If either of
the radii are negative, throws an INDEX_SIZE_ERR p70 exception.
The addColorStop(offset, color) method on the CanvasGradient p242 interface adds a new stop to a gradient.
If the offset is less than 0, greater than 1, infinite, or NaN, then an INDEX_SIZE_ERR p70 exception must be raised. If
the color cannot be parsed as a CSS color, then a SYNTAX_ERR p70 exception must be raised. Otherwise, the
gradient must have a new stop placed, at offset offset relative to the whole gradient, and with the color obtained
by parsing color as a CSS value. If multiple stops are added at the same offset on a gradient, they must
be placed in the order added, with the first one closest to the start of the gradient, and each subsequent one
infinitesimally further along towards the end point (in effect causing all but the first and last stop added at each
point to be ignored).
The createLinearGradient(x0, y0, x1, y1) method takes four arguments that represent the start point (x0,
y0) and end point (x1, y1) of the gradient. If any of the arguments to createLinearGradient() p246 are infinite or
246
NaN, the method must raise a NOT_SUPPORTED_ERR p70 exception. Otherwise, the method must return a linear
CanvasGradient p242 initialized with the specified line.
Linear gradients must be rendered such that all points on a line perpendicular to the line that crosses the start and
end points have the color at the point where those two lines cross (with the colors coming from the interpolation
and extrapolation p246 described above). The points in the linear gradient must be transformed as described by the
current transformation matrix p243 when rendering.
If x0 = x1 and y0 = y1, then the linear gradient must paint nothing.
The createRadialGradient(x0, y0, r0, x1, y1, r1) method takes six arguments, the first three representing
the start circle with origin (x0, y0) and radius r0, and the last three representing the end circle with origin (x1, y1)
and radius r1. The values are in coordinate space units. If any of the arguments are infinite or NaN, a
NOT_SUPPORTED_ERR p70 exception must be raised. If either of r0 or r1 are negative, an INDEX_SIZE_ERR p70
exception must be raised. Otherwise, the method must return a radial CanvasGradient p242 initialized with the two
specified circles.
Radial gradients must be rendered by following these steps:
1.
If x0 = x1 and y0 = y1 and r0 = r1, then the radial gradient must paint nothing. Abort these steps.
2.
Let x(ω) = (x1-x0)ω + x0
Let y(ω) = (y1-y0)ω + y0
Let r(ω) = (r1-r0)ω + r0
Let the color at ω be the color at that position on the gradient (with the colors coming from the
interpolation and extrapolation p246 described above).
3.
For all values of ω where r(ω) > 0, starting with the value of ω nearest to positive infinity and ending
with the value of ω nearest to negative infinity, draw the circumference of the circle with radius r(ω) at
position (x(ω), y(ω)), with the color at ω, but only painting on the parts of the canvas that have not yet
been painted on by earlier circles in this step for this rendering of the gradient.
Note: This effectively creates a cone, touched by the two circles defined in the creation of the
gradient, with the part of the cone before the start circle (0.0) using the color of the first
offset, the part of the cone after the end circle (1.0) using the color of the last offset, and
areas outside the cone untouched by the gradient (transparent black).
The points in the radial gradient must be transformed as described by the current transformation matrix p243 when
rendering.
Gradients must be painted only where the relevant stroking or filling effects requires that they be drawn.
Patterns are represented by objects implementing the opaque CanvasPattern p242 interface.
This box is non-normative. Implementation requirements are given below this box.
pattern = context . createPattern p247 (image, repetition)
Returns a CanvasPattern p242 object that uses the given image and repeats in the direction(s) given by
the repetition argument.
The allowed values for repetition are repeat (both directions), repeat-x (horizontal only), repeat-y
(vertical only), and no-repeat (neither). If the repetition argument is empty or null, the value repeat
is used.
If the first argument isn't an img p186 , canvas p238 , or video p213 element, throws a TYPE_MISMATCH_ERR p70
exception. If the image has no image data, throws an INVALID_STATE_ERR p70 exception. If the second
argument isn't one of the allowed values, throws a SYNTAX_ERR p70 exception. If the image isn't yet fully
decoded, then the method returns null.
To create objects of this type, the createPattern(image, repetition) method is used. The first argument gives
the image to use as the pattern (either an HTMLImageElement p186 , HTMLCanvasElement p238 , or
HTMLVideoElement p214 object). Modifying this image after calling the createPattern() p247 method must not affect
the pattern. The second argument must be a string with one of the following values: repeat, repeat-x, repeat-y,
no-repeat. If the empty string or null is specified, repeat must be assumed. If an unrecognized value is given,
then the user agent must raise a SYNTAX_ERR p70 exception. User agents must recognize the four values described
above exactly (e.g. they must not do case folding). The method must return a CanvasPattern p242 object suitably
initialized.
247
The image argument is an instance of either HTMLImageElement p186 , HTMLCanvasElement p238 , or
HTMLVideoElement p214 . If the image is null, the implementation must raise a TYPE_MISMATCH_ERR p70 exception.
If the image argument is an HTMLImageElement p186 object whose complete p189 attribute is false, or if the image
argument is an HTMLVideoElement p214 object whose readyState p231 attribute is either HAVE_NOTHING p229 or
HAVE_METADATA p229 , then the implementation must return null.
If the image argument is an HTMLCanvasElement p238 object with either a horizontal dimension or a vertical
dimension equal to zero, then the implementation must raise an INVALID_STATE_ERR p70 exception.
Patterns must be painted so that the top left of the first image is anchored at the origin of the coordinate space,
and images are then repeated horizontally to the left and right (if the repeat-x string was specified) or vertically
up and down (if the repeat-y string was specified) or in all four directions all over the canvas (if the repeat string
was specified). The images are not scaled by this process; one CSS pixel of the image must be painted on one
coordinate space unit. Of course, patterns must actually be painted only where the stroking or filling effect
requires that they be drawn, and are affected by the current transformation matrix.
When the createPattern() p247 method is passed an animated image as its image argument, the user agent must
use the poster frame of the animation, or, if there is no poster frame, the first frame of the animation.
When the image argument is an HTMLVideoElement p214 , then the frame at the current playback position p229 must
be used as the source image, and the source image's dimensions must be the intrinsic width p215 and intrinsic
height p215 of the media resource p219 (i.e. after any aspect-ratio correction has been applied).
4.8.10.1.5 Line styles
This box is non-normative. Implementation requirements are given below this box.
context . lineWidth
p248
[ = value ]
Returns the current line width.
Can be set, to change the line width. Values that are not finite values greater than zero are ignored.
context . lineCap p248 [ = value ]
Returns the current line cap style.
Can be set, to change the line cap style.
The possible line cap styles are butt, round, and square. Other values are ignored.
context . lineJoin p249 [ = value ]
Returns the current line join style.
Can be set, to change the line join style.
The possible line join styles are bevel, round, and miter. Other values are ignored.
context . miterLimit p249 [ = value ]
Returns the current miter limit ratio.
Can be set, to change the miter limit ratio. Values that are not finite values greater than zero are
ignored.
The lineWidth attribute gives the width of lines, in coordinate space units. On getting, it must return the current
value. On setting, zero, negative, infinite, and NaN values must be ignored, leaving the value unchanged; other
values must change the current value to the new value.
When the context is created, the lineWidth p248 attribute must initially have the value 1.0.
The lineCap attribute defines the type of endings that UAs will place on the end of lines. The three valid values
are butt, round, and square. The butt value means that the end of each line has a flat edge perpendicular to the
direction of the line (and that no additional line cap is added). The round value means that a semi-circle with the
diameter equal to the width of the line must then be added on to the end of the line. The square value means that
a rectangle with the length of the line width and the width of half the line width, placed flat against the edge
perpendicular to the direction of the line, must be added at the end of each line.
On getting, it must return the current value. On setting, if the new value is one of the literal strings butt, round,
and square, then the current value must be changed to the new value; other values must ignored, leaving the
value unchanged.
When the context is created, the lineCap p248 attribute must initially have the value butt.
248
The lineJoin attribute defines the type of corners that UAs will place where two lines meet. The three valid
values are bevel, round, and miter.
On getting, it must return the current value. On setting, if the new value is one of the literal strings bevel, round,
and miter, then the current value must be changed to the new value; other values must be ignored, leaving the
value unchanged.
When the context is created, the lineJoin p249 attribute must initially have the value miter.
A join exists at any point in a subpath shared by two consecutive lines. When a subpath is closed, then a join also
exists at its first point (equivalent to its last point) connecting the first and last lines in the subpath.
In addition to the point where the join occurs, two additional points are relevant to each join, one for each line: the
two corners found half the line width away from the join point, one perpendicular to each line, each on the side
furthest from the other line.
A filled triangle connecting these two opposite corners with a straight line, with the third point of the triangle being
the join point, must be rendered at all joins. The lineJoin p249 attribute controls whether anything else is rendered.
The three aforementioned values have the following meanings:
The bevel value means that this is all that is rendered at joins.
The round value means that a filled arc connecting the two aforementioned corners of the join, abutting (and not
overlapping) the aforementioned triangle, with the diameter equal to the line width and the origin at the point of
the join, must be rendered at joins.
The miter value means that a second filled triangle must (if it can given the miter length) be rendered at the join,
with one line being the line between the two aforementioned corners, abutting the first triangle, and the other two
being continuations of the outside edges of the two joining lines, as long as required to intersect without going
over the miter length.
The miter length is the distance from the point where the join occurs to the intersection of the line edges on the
outside of the join. The miter limit ratio is the maximum allowed ratio of the miter length to half the line width. If
the miter length would cause the miter limit ratio to be exceeded, this second triangle must not be rendered.
The miter limit ratio can be explicitly set using the miterLimit attribute. On getting, it must return the current
value. On setting, zero, negative, infinite, and NaN values must be ignored, leaving the value unchanged; other
values must change the current value to the new value.
When the context is created, the miterLimit p249 attribute must initially have the value 10.0.
4.8.10.1.6 Shadows
All drawing operations are affected by the four global shadow attributes.
This box is non-normative. Implementation requirements are given below this box.
context . shadowColor p249 [ = value ]
Returns the current shadow color.
Can be set, to change the shadow color. Values that cannot be parsed as CSS colors are ignored.
context . shadowOffsetX p250 [ = value ]
context . shadowOffsetY p250 [ = value ]
Returns the current shadow offset.
Can be set, to change the shadow offset. Values that are not finite numbers are ignored.
context . shadowBlur p250 [ = value ]
Returns the current level of blur applied to shadows.
Can be set, to change the blur level. Values that are not finite numbers greater than or equal to zero
are ignored.
The shadowColor attribute sets the color of the shadow.
When the context is created, the shadowColor p249 attribute initially must be fully-transparent black.
On getting, the serialization of the color p246 must be returned.
On setting, the new value must be parsed as a CSS value and the color assigned. If the value is not a
valid color, then it must be ignored, and the attribute must retain its previous value. [CSSCOLOR] p700
249
The shadowOffsetX and shadowOffsetY attributes specify the distance that the shadow will be offset in the
positive horizontal and positive vertical distance respectively. Their values are in coordinate space units. They are
not affected by the current transformation matrix.
When the context is created, the shadow offset attributes must initially have the value 0.
On getting, they must return their current value. On setting, the attribute being set must be set to the new value,
except if the value is infinite or NaN, in which case the new value must be ignored.
The shadowBlur attribute specifies the size of the blurring effect. (The units do not map to coordinate space units,
and are not affected by the current transformation matrix.)
When the context is created, the shadowBlur p250 attribute must initially have the value 0.
On getting, the attribute must return its current value. On setting the attribute must be set to the new value,
except if the value is negative, infinite or NaN, in which case the new value must be ignored.
Shadows are only drawn if the opacity component of the alpha component of the color of shadowColor p249 is
non-zero and either the shadowBlur p250 is non-zero, or the shadowOffsetX p250 is non-zero, or the
shadowOffsetY p250 is non-zero.
When shadows are drawn p250 , they must be rendered as follows:
1.
Let A be an infinite transparent black bitmap on which the source image for which a shadow is being
created has been rendered.
2.
Let B be an infinite transparent black bitmap, with a coordinate space and an origin identical to A.
3.
Copy the alpha channel of A to B, offset by shadowOffsetX p250 in the positive x direction, and
shadowOffsetY p250 in the positive y direction.
4.
If shadowBlur p250 is greater than 0:
1.
If shadowBlur p250 is less than 8, let σ be half the value of shadowBlur p250 ; otherwise, let σ be
the square root of multiplying the value of shadowBlur p250 by 2.
2.
Perform a 2D Gaussian Blur on B, using σ as the standard deviation.
User agents may limit values of σ to an implementation-specific maximum value to avoid exceeding
hardware limitations during the Gaussian blur operation.
5.
Set the red, green, and blue components of every pixel in B to the red, green, and blue components
(respectively) of the color of shadowColor p249 .
6.
Multiply the alpha component of every pixel in B by the alpha component of the color of
shadowColor p249 .
7.
The shadow is in the bitmap B, and is rendered as part of the drawing model described below.
If the current composition operation is copy p245 , shadows effectively won't render (since the shape will overwrite
the shadow).
4.8.10.1.7 Simple shapes (rectangles)
There are three methods that immediately draw rectangles to the bitmap. They each take four arguments; the first
two give the x and y coordinates of the top left of the rectangle, and the second two give the width w and height h
of the rectangle, respectively.
The current transformation matrix p243 must be applied to the following four coordinates, which form the path that
must then be closed to get the specified rectangle: (x, y), (x+w, y), (x+w, y+h), (x, y+h).
Shapes are painted without affecting the current path, and are subject to the clipping region p253 , and, with the
exception of clearRect() p251 , also shadow effects p249 , global alpha p244 , and global composition operators p244 .
This box is non-normative. Implementation requirements are given below this box.
context . clearRect
p251
(x, y, w, h)
Clears all pixels on the canvas in the given rectangle to transparent black.
context . fillRect p251 (x, y, w, h)
Paints the given rectangle onto the canvas, using the current fill style.
250
context . strokeRect p251 (x, y, w, h)
Paints the box that outlines the given rectangle onto the canvas, using the current stroke style.
The clearRect(x, y, w, h) method must clear the pixels in the specified rectangle that also intersect the
current clipping region to a fully transparent black, erasing any previous image. If either height or width are zero,
this method has no effect.
The fillRect(x, y, w, h) method must paint the specified rectangular area using the fillStyle p245 . If either
height or width are zero, this method has no effect.
The strokeRect(x, y, w, h) method must stroke the specified rectangle's path using the strokeStyle p245 ,
lineWidth p248 , lineJoin p249 , and (if appropriate) miterLimit p249 attributes. If both height and width are zero, this
method has no effect, since there is no path to stroke (it's a point). If only one of the two is zero, then the method
will draw a line instead (the path for the outline is just a straight line along the non-zero dimension).
4.8.10.1.8 Complex shapes (paths)
The context always has a current path. There is only one current path, it is not part of the drawing state p243 .
A path has a list of zero or more subpaths. Each subpath consists of a list of one or more points, connected by
straight or curved lines, and a flag indicating whether the subpath is closed or not. A closed subpath is one where
the last point of the subpath is connected to the first point of the subpath by a straight line. Subpaths with fewer
than two points are ignored when painting the path.
This box is non-normative. Implementation requirements are given below this box.
context . beginPath p252 ()
Resets the current path.
context . moveTo p252 (x, y)
Creates a new subpath with the given point.
context . closePath p252 ()
Marks the current subpath as closed, and starts a new subpath with a point the same as the start and
end of the newly closed subpath.
context . lineTo p252 (x, y)
Adds the given point to the current subpath, connected to the previous one by a straight line.
context . quadraticCurveTo p252 (cpx, cpy, x, y)
Adds the given point to the current path, connected to the previous one by a quadratic Bézier curve
with the given control point.
context . bezierCurveTo p252 (cp1x, cp1y, cp2x, cp2y, x, y)
Adds the given point to the current path, connected to the previous one by a cubic Bézier curve with
the given control points.
context . arcTo p252 (x1, y1, x2, y2, radius)
Adds a point to the current path, connected to the previous one by a straight line, then adds a second
point to the current path, connected to the previous one by an arc whose properties are described by
the arguments.
Throws an INDEX_SIZE_ERR p70 exception if the given radius is negative.
context . arc p252 (x, y, radius, startAngle, endAngle, anticlockwise)
Adds points to the subpath such that the arc described by the circumference of the circle described by
the arguments, starting at the given start angle and ending at the given end angle, going in the given
direction, is added to the path, connected to the previous point by a straight line.
Throws an INDEX_SIZE_ERR p70 exception if the given radius is negative.
context . rect p253 (x, y, w, h)
Adds a new closed subpath to the path, representing the given rectangle.
context . fill p253 ()
Fills the subpaths with the current fill style.
251
context . stroke p253 ()
Strokes the subpaths with the current stroke style.
context . clip p253 ()
Further constrains the clipping region to the given path.
context . isPointInPath p253 (x, y)
Returns true if the given point is in the current path.
Initially, the context's path must have zero subpaths.
The points and lines added to the path by these methods must be transformed according to the current
transformation matrix p243 as they are added.
The beginPath() method must empty the list of subpaths so that the context once again has zero subpaths.
The moveTo(x, y) method must create a new subpath with the specified point as its first (and only) point.
When the user agent is to ensure there is a subpath for a coordinate (x, y), the user agent must check to see if
the context has any subpaths, and if it does not, then the user agent must create a new subpath with the point (x,
y) as its first (and only) point, as if the moveTo() p252 method had been called.
The closePath() method must do nothing if the context has no subpaths. Otherwise, it must mark the last
subpath as closed, create a new subpath whose first point is the same as the previous subpath's first point, and
finally add this new subpath to the path.
Note: If the last subpath had more than one point in its list of points, then this is equivalent to
adding a straight line connecting the last point back to the first point, thus "closing" the
shape, and then repeating the last (possibly implied) moveTo() p252 call.
New points and the lines connecting them are added to subpaths using the methods described below. In all cases,
the methods only modify the last subpath in the context's paths.
The lineTo(x, y) method must ensure there is a subpath p252 for (x, y) if the context has no subpaths. Otherwise,
it must connect the last point in the subpath to the given point (x, y) using a straight line, and must then add the
given point (x, y) to the subpath.
The quadraticCurveTo(cpx, cpy, x, y) method must ensure there is a subpath p252 for (cpx, cpy), and then
must connect the last point in the subpath to the given point (x, y) using a quadratic Bézier curve with control
point (cpx, cpy), and must then add the given point (x, y) to the subpath. [BEZIER] p700
The bezierCurveTo(cp1x, cp1y, cp2x, cp2y, x, y) method must ensure there is a subpath p252 for (cp1x,
cp1y), and then must connect the last point in the subpath to the given point (x, y) using a cubic Bézier curve with
control points (cp1x, cp1y) and (cp2x, cp2y). Then, it must add the point (x, y) to the subpath. [BEZIER] p700
The arcTo(x1, y1, x2, y2, radius) method must first ensure there is a subpath p252 for (x1, y1). Then, the
behavior depends on the arguments and the last point in the subpath, as described below.
Negative values for radius must cause the implementation to raise an INDEX_SIZE_ERR p70 exception.
Let the point (x0, y0) be the last point in the subpath.
If the point (x0, y0) is equal to the point (x1, y1), or if the point (x1, y1) is equal to the point (x2, y2), or if the
radius radius is zero, then the method must add the point (x1, y1) to the subpath, and connect that point to the
previous point (x0, y0) by a straight line.
Otherwise, if the points (x0, y0), (x1, y1), and (x2, y2) all lie on a single straight line, then the method must add
the point (x1, y1) to the subpath, and connect that point to the previous point (x0, y0) by a straight line.
Otherwise, let The Arc be the shortest arc given by circumference of the circle that has radius radius, and that has
one point tangent to the half-infinite line that crosses the point (x0, y0) and ends at the point (x1, y1), and that
has a different point tangent to the half-infinite line that ends at the point (x1, y1) and crosses the point (x2, y2).
The points at which this circle touches these two lines are called the start and end tangent points respectively. The
method must connect the point (x0, y0) to the start tangent point by a straight line, adding the start tangent point
to the subpath, and then must connect the start tangent point to the end tangent point by The Arc, adding the end
tangent point to the subpath.
The arc(x, y, radius, startAngle, endAngle, anticlockwise) method draws an arc. If the context has any
subpaths, then the method must add a straight line from the last point in the subpath to the start point of the arc.
252
In any case, it must draw the arc between the start point of the arc and the end point of the arc, and add the start
and end points of the arc to the subpath. The arc and its start and end points are defined as follows:
Consider a circle that has its origin at (x, y) and that has radius radius. The points at startAngle and endAngle
along this circle's circumference, measured in radians clockwise from the positive x-axis, are the start and end
points respectively.
If the anticlockwise argument is false and endAngle-startAngle is equal to or greater than 2π, or, if the
anticlockwise argument is true and startAngle-endAngle is equal to or greater than 2π, then the arc is the whole
circumference of this circle.
Otherwise, the arc is the path along the circumference of this circle from the start point to the end point, going
anti-clockwise if the anticlockwise argument is true, and clockwise otherwise. Since the points are on the circle, as
opposed to being simply angles from zero, the arc can never cover an angle greater than 2π radians. If the two
points are the same, or if the radius is zero, then the arc is defined as being of zero length in both directions.
Negative values for radius must cause the implementation to raise an INDEX_SIZE_ERR p70 exception.
The rect(x, y, w, h) method must create a new subpath containing just the four points (x, y), (x+w, y), (x+w,
y+h), (x, y+h), with those four points connected by straight lines, and must then mark the subpath as closed. It
must then create a new subpath with the point (x, y) as the only point in the subpath.
The fill() method must fill all the subpaths of the current path, using fillStyle p245 , and using the non-zero
winding number rule. Open subpaths must be implicitly closed when being filled (without affecting the actual
subpaths).
Note: Thus, if two overlapping but otherwise independent subpaths have opposite windings,
they cancel out and result in no fill. If they have the same winding, that area just gets painted
once.
The stroke() method must calculate the strokes of all the subpaths of the current path, using the lineWidth p248 ,
lineCap p248 , lineJoin p249 , and (if appropriate) miterLimit p249 attributes, and then fill the combined stroke area
using the strokeStyle p245 attribute.
Note: Since the subpaths are all stroked as one, overlapping parts of the paths in one stroke
operation are treated as if their union was what was painted.
Paths, when filled or stroked, must be painted without affecting the current path, and must be subject to shadow
effects p249 , global alpha p244 , the clipping region p253 , and global composition operators p244 . (Transformations affect
the path when the path is created, not when it is painted, though the stroke style is still affected by the
transformation during painting.)
Zero-length line segments must be pruned before stroking a path. Empty subpaths must be ignored.
The clip() method must create a new clipping region by calculating the intersection of the current clipping
region and the area described by the current path, using the non-zero winding number rule. Open subpaths must
be implicitly closed when computing the clipping region, without affecting the actual subpaths. The new clipping
region replaces the current clipping region.
When the context is initialized, the clipping region must be set to the rectangle with the top left corner at (0,0) and
the width and height of the coordinate space.
The isPointInPath(x, y) method must return true if the point given by the x and y coordinates passed to the
method, when treated as coordinates in the canvas coordinate space unaffected by the current transformation, is
inside the current path as determined by the non-zero winding number rule; and must return false otherwise.
Points on the path itself are considered to be inside the path. If either of the arguments is infinite or NaN, then the
method must return false.
4.8.10.1.9 Focus management
When a canvas is interactive, authors should include focusable elements in the element's fallback content
corresponding to each focusable part of the canvas.
To indicate which focusable part of the canvas is currently focused, authors should use the drawFocusRing() p254
method, passing it the element for which a ring is being drawn. This method only draws the focus ring if the
element is focused, so that it can simply be called whenever drawing the element, without checking whether the
element is focused or not first. The position of the center of the control, or of the editing caret if the control has
one, should be given in the x and y arguments.
253
This box is non-normative. Implementation requirements are given below this box.
shouldDraw = context . drawFocusRing p254 (element, x, y, [ canDrawCustom ])
If the given element is focused, draws a focus ring around the current path, following the platform
conventions for focus rings. The given coordinate is used if the user's attention needs to be brought to
a particular position (e.g. if a magnifier is following the editing caret in a text field).
If the canDrawCustom argument is true, then the focus ring is only drawn if the user has configured
his system to draw focus rings in a particular manner. (For example, high contrast focus rings.)
Returns true if the given element is focused, the canDrawCustom argument is true, and the user has
not configured his system to draw focus rings in a particular manner. Otherwise, returns false.
When the method returns true, the author is expected to manually draw a focus ring.
The drawFocusRing(element, x, y, [canDrawCustom]) method, when invoked, must run the following steps:
1.
If element is not focused or is not a descendant of the element with whose context the method is
associated, then return false and abort these steps.
2.
Transform the given point (x, y) according to the current transformation matrix p243 .
3.
Optionally, inform the user that the focus is at the given (transformed) coordinate on the canvas. (For
example, this could involve moving the user's magnification tool.)
4.
If the user has requested the use of particular focus rings (e.g. high-contrast focus rings), or if the
canDrawCustom argument is absent or false, then draw a focus ring of the appropriate style along the
path, following platform conventions, return false, and abort these steps.
The focus ring should not be subject to the shadow effects p249 , the global alpha p244 , or the global
composition operators p244 , but should be subject to the clipping region p253 .
5.
Return true.
This canvas p238 element has a couple of checkboxes:
4.8.10.1.10 Text
This box is non-normative. Implementation requirements are given below this box.
context . font p255 [ = value ]
Returns the current font settings.
Can be set, to change the font. The syntax is the same as for the CSS 'font' property; values that
cannot be parsed as CSS font values are ignored.
Relative keywords and lengths are computed relative to the font of the canvas p238 element.
context . textAlign p256 [ = value ]
Returns the current text alignment settings.
Can be set, to change the alignment. The possible values are start, end, left, right, and center.
Other values are ignored. The default is start.
context . textBaseline p256 [ = value ]
Returns the current baseline alignment settings.
Can be set, to change the baseline alignment. The possible values and their meanings are given
below. Other values are ignored. The default is alphabetic.
context . fillText p257 (text, x, y [, maxWidth ] )
context . strokeText p257 (text, x, y [, maxWidth ] )
Fills or strokes (respectively) the given text at the given position. If a maximum width is provided, the
text will be scaled to fit that width if necessary.
metrics = context . measureText p258 (text)
Returns a TextMetrics p242 object with the metrics of the given text in the current font.
metrics . width p258
Returns the advance width of the text that was passed to the measureText() p258 method.
The font IDL attribute, on setting, must be parsed the same way as the 'font' property of CSS (but without
supporting property-independent style sheet syntax like 'inherit'), and the resulting font must be assigned to the
context, with the 'line-height' component forced to 'normal', with the 'font-size' component converted to CSS
pixels, and with system fonts being computed to explicit values. If the new value is syntactically incorrect
255
(including using property-independent style sheet syntax like 'inherit' or 'initial'), then it must be ignored, without
assigning a new font value. [CSS] p700
Font names must be interpreted in the context of the canvas p238 element's stylesheets; any fonts embedded using
@font-face must therefore be available once they are loaded. (If a font is referenced before it is fully loaded, then
it must be treated as if it was an unknown font, falling back to another as described by the relevant CSS
specifications.) [CSSFONTS] p700
Only vector fonts should be used by the user agent; if a user agent were to use bitmap fonts then transformations
would likely make the font look very ugly.
On getting, the font p255 attribute must return the serialized form of the current font of the context (with no 'lineheight' component). [CSSOM] p700
For example, after the following statement:
context.font = 'italic 400 12px/2 Unknown Font, sans-serif';
...the expression context.font would evaluate to the string "italic 12px "Unknown Font", sansserif". The "400" font-weight doesn't appear because that is the default value. The line-height doesn't
appear because it is forced to "normal", the default value.
When the context is created, the font of the context must be set to 10px sans-serif. When the 'font-size'
component is set to lengths using percentages, 'em' or 'ex' units, or the 'larger' or 'smaller' keywords, these must
be interpreted relative to the computed value of the 'font-size' property of the corresponding canvas p238 element
at the time that the attribute is set. When the 'font-weight' component is set to the relative values 'bolder' and
'lighter', these must be interpreted relative to the computed value of the 'font-weight' property of the
corresponding canvas p238 element at the time that the attribute is set. If the computed values are undefined for a
particular case (e.g. because the canvas p238 element is not in a Document p27 ), then the relative keywords must be
interpreted relative to the normal-weight 10px sans-serif default.
The textAlign IDL attribute, on getting, must return the current value. On setting, if the value is one of start,
end, left, right, or center, then the value must be changed to the new value. Otherwise, the new value must be
ignored. When the context is created, the textAlign p256 attribute must initially have the value start.
The textBaseline IDL attribute, on getting, must return the current value. On setting, if the value is one of
top p256 , hanging p256 , middle p256 , alphabetic p256 , ideographic p257 , or bottom p257 , then the value must be changed
to the new value. Otherwise, the new value must be ignored. When the context is created, the textBaseline p256
attribute must initially have the value alphabetic.
The textBaseline p256 attribute's allowed keywords correspond to alignment points in the font:
The keywords map to these alignment points as follows:
top
The top of the em square
hanging
The hanging baseline
middle
The middle of the em square
alphabetic
The alphabetic baseline
256
ideographic
The ideographic baseline
bottom
The bottom of the em square
The fillText() and strokeText() methods take three or four arguments, text, x, y, and optionally maxWidth,
and render the given text at the given (x, y) coordinates ensuring that the text isn't wider than maxWidth if
specified, using the current font p255 , textAlign p256 , and textBaseline p256 values. Specifically, when the methods
are called, the user agent must run the following steps:
1.
Let font be the current font of the context, as given by the font p255 attribute.
2.
Replace all the space characters p34 in text with U+0020 SPACE characters.
3.
Form a hypothetical infinitely wide CSS line box containing a single inline box containing the text text,
with all the properties at their initial values except the 'font' property of the inline box set to font and the
'direction' property of the inline box set to the directionality p86 of the canvas p238 element. [CSS] p700
4.
If the maxWidth argument was specified and the hypothetical width of the inline box in the hypothetical
line box is greater than maxWidth CSS pixels, then change font to have a more condensed font (if one is
available or if a reasonably readable one can be synthesized by applying a horizontal scale factor to the
font) or a smaller font, and return to the previous step.
5.
Let the anchor point be a point on the inline box, determined by the textAlign p256 and
textBaseline p256 values, as follows:
Horizontal position:
If textAlign p256 is left
If textAlign p256 is start and the directionality p86 of the canvas p238 element is 'ltr'
If textAlign p256 is end and the directionality p86 of the canvas p238 element is 'rtl'
Let the anchor point's horizontal position be the left edge of the inline box.
If textAlign p256 is right
If textAlign p256 is end and the directionality p86 of the canvas p238 element is 'ltr'
If textAlign p256 is start and the directionality p86 of the canvas p238 element is 'rtl'
Let the anchor point's horizontal position be the right edge of the inline box.
If textAlign p256 is center
Let the anchor point's horizontal position be half way between the left and right edges of the inline
box.
Vertical position:
If textBaseline p256 is top p256
Let the anchor point's vertical position be the top of the em box of the first available font of the
inline box.
If textBaseline p256 is hanging p256
Let the anchor point's vertical position be the hanging baseline of the first available font of the
inline box.
If textBaseline p256 is middle p256
Let the anchor point's vertical position be half way between the bottom and the top of the em box
of the first available font of the inline box.
If textBaseline p256 is alphabetic p256
Let the anchor point's vertical position be the alphabetic baseline of the first available font of the
inline box.
If textBaseline p256 is ideographic p257
Let the anchor point's vertical position be the ideographic baseline of the first available font of the
inline box.
If textBaseline p256 is bottom p257
Let the anchor point's vertical position be the bottom of the em box of the first available font of the
inline box.
6.
Paint the hypothetical inline box as the shape given by the text's glyphs, as transformed by the current
transformation matrix p243 , and anchored and sized so that before applying the current transformation
matrix p243 , the anchor point is at (x, y) and each CSS pixel is mapped to one coordinate space unit.
257
For fillText() p257 fillStyle p245 must be applied to the glyphs and strokeStyle p245 must be ignored.
For strokeText() p257 the reverse holds and strokeStyle p245 must be applied to the glyph outlines and
fillStyle p245 must be ignored.
Text is painted without affecting the current path, and is subject to shadow effects p249 , global alpha p244 ,
the clipping region p253 , and global composition operators p244 .
The measureText() method takes one argument, text. When the method is invoked, the user agent must replace
all the space characters p34 in text with U+0020 SPACE characters, and then must form a hypothetical infinitely
wide CSS line box containing a single inline box containing the text text, with all the properties at their initial
values except the 'font' property of the inline element set to the current font of the context, as given by the
font p255 attribute, and must then return a new TextMetrics p242 object with its width p258 attribute set to the width
of that inline box, in CSS pixels. [CSS] p700
The TextMetrics p242 interface is used for the objects returned from measureText() p258 . It has one attribute,
width, which is set by the measureText() p258 method.
Note: Glyphs rendered using fillText() p257 and strokeText() p257 can spill out of the box given
by the font size (the em square size) and the width returned by measureText() p258 (the text
width). This version of the specification does not provide a way to obtain the bounding box
dimensions of the text. If the text is to be rendered and removed, care needs to be taken to
replace the entire area of the canvas that the clipping region covers, not just the box given by
the em square height and measured text width.
Note: A future version of the 2D context API may provide a way to render fragments of
documents, rendered using CSS, straight to the canvas. This would be provided in preference
to a dedicated way of doing multiline layout.
4.8.10.1.11 Images
To draw images onto the canvas, the drawImage method can be used.
This method can be invoked with three different sets of arguments:
•
•
•
drawImage(image, dx, dy)
drawImage(image, dx, dy, dw, dh)
drawImage(image, sx, sy, sw, sh, dx, dy, dw, dh)
Each of those three can take either an HTMLImageElement p186 , an HTMLCanvasElement p238 , or an
HTMLVideoElement p214 for the image argument.
This box is non-normative. Implementation requirements are given below this box.
context . drawImage p258 (image, dx, dy)
context . drawImage p258 (image, dx, dy, dw, dh)
context . drawImage p258 (image, sx, sy, sw, sh, dx, dy, dw, dh)
Draws the given image onto the canvas. The arguments are interpreted as follows:
258
If the first argument isn't an img p186 , canvas p238 , or video p213 element, throws a TYPE_MISMATCH_ERR p70
exception. If the image has no image data, throws an INVALID_STATE_ERR p70 exception. If the numeric
arguments don't make sense (e.g. the destination is a 0×0 rectangle), throws an INDEX_SIZE_ERR p70
exception. If the image isn't yet fully decoded, then nothing is drawn.
If not specified, the dw and dh arguments must default to the values of sw and sh, interpreted such that one CSS
pixel in the image is treated as one unit in the canvas coordinate space. If the sx, sy, sw, and sh arguments are
omitted, they must default to 0, 0, the image's intrinsic width in image pixels, and the image's intrinsic height in
image pixels, respectively.
The image argument is an instance of either HTMLImageElement p186 , HTMLCanvasElement p238 , or
HTMLVideoElement p214 . If the image is null, the implementation must raise a TYPE_MISMATCH_ERR p70 exception.
If the image argument is an HTMLImageElement p186 object whose complete p189 attribute is false, or if the image
argument is an HTMLVideoElement p214 object whose readyState p231 attribute is either HAVE_NOTHING p229 or
HAVE_METADATA p229 , then the implementation must return without drawing anything.
If the image argument is an HTMLCanvasElement p238 object with either a horizontal dimension or a vertical
dimension equal to zero, then the implementation must raise an INVALID_STATE_ERR p70 exception.
The source rectangle is the rectangle whose corners are the four points (sx, sy), (sx+sw, sy), (sx+sw, sy+sh), (sx,
sy+sh).
If the source rectangle is not entirely within the source image, or if one of the sw or sh arguments is zero, the
implementation must raise an INDEX_SIZE_ERR p70 exception.
The destination rectangle is the rectangle whose corners are the four points (dx, dy), (dx+dw, dy), (dx+dw,
dy+dh), (dx, dy+dh).
When drawImage() p258 is invoked, the region of the image specified by the source rectangle must be painted on
the region of the canvas specified by the destination rectangle, after applying the current transformation
matrix p243 to the points of the destination rectangle.
The original image data of the source image must be used, not the image as it is rendered (e.g. width p271 and
height p271 attributes on the source element have no effect). The image data must be processed in the original
direction, even if the dimensions given are negative.
Note: This specification does not define the algorithm to use when scaling the image, if
necessary.
Note: When a canvas is drawn onto itself, the drawing model requires the source to be copied
before the image is drawn back onto the canvas, so it is possible to copy parts of a canvas
onto overlapping parts of itself.
259
When the drawImage() p258 method is passed an animated image as its image argument, the user agent must use
the poster frame of the animation, or, if there is no poster frame, the first frame of the animation.
When the image argument is an HTMLVideoElement p214 , then the frame at the current playback position p229 must
be used as the source image, and the source image's dimensions must be the intrinsic width p215 and intrinsic
height p215 of the media resource p219 (i.e. after any aspect-ratio correction has been applied).
Images are painted without affecting the current path, and are subject to shadow effects p249 , global alpha p244 , the
clipping region p253 , and global composition operators p244 .
4.8.10.1.12 Pixel manipulation
This box is non-normative. Implementation requirements are given below this box.
imagedata = context . createImageData p260 (sw, sh)
Returns an ImageData p242 object with the given dimensions in CSS pixels (which might map to a
different number of actual device pixels exposed by the object itself). All the pixels in the returned
object are transparent black.
imagedata = context . createImageData p260 (imagedata)
Returns an ImageData p242 object with the same dimensions as the argument. All the pixels in the
returned object are transparent black.
Throws a NOT_SUPPORTED_ERR p70 exception if the argument is null.
imagedata = context . getImageData p260 (sx, sy, sw, sh)
Returns an ImageData p242 object containing the image data for the given rectangle of the canvas.
Throws a NOT_SUPPORTED_ERR p70 exception if any of the arguments are not finite. Throws an
INDEX_SIZE_ERR p70 exception if the either of the width or height arguments are zero.
imagedata . width p260
imagedata . height p260
Returns the actual dimensions of the data in the ImageData p242 object, in device pixels.
imagedata . data p261
Returns the one-dimensional array containing the data in RGBA order, as integers in the range 0 to
255.
context . putImageData p261 (imagedata, dx, dy [, dirtyX, dirtyY, dirtyWidth, dirtyHeight ])
Paints the data from the given ImageData p242 object onto the canvas. If a dirty rectangle is provided,
only the pixels from that rectangle are painted.
The globalAlpha p244 and globalCompositeOperation p244 attributes, as well as the shadow attributes,
are ignored for the purposes of this method call; pixels in the canvas are replaced wholesale, with no
composition, alpha blending, no shadows, etc.
If the first argument isn't an ImageData p242 object, throws a TYPE_MISMATCH_ERR p70 exception. Throws
a NOT_SUPPORTED_ERR p70 exception if any of the other arguments are not finite.
The createImageData() method is used to instantiate new blank ImageData p242 objects. When the method is
invoked with two arguments sw and sh, it must return an ImageData p242 object representing a rectangle with a
width in CSS pixels equal to the absolute magnitude of sw and a height in CSS pixels equal to the absolute
magnitude of sh. When invoked with a single imagedata argument, it must return an ImageData p242 object
representing a rectangle with the same dimensions as the ImageData p242 object passed as the argument. The
ImageData p242 object return must be filled with transparent black.
The getImageData(sx, sy, sw, sh) method must return an ImageData p242 object representing the underlying
pixel data for the area of the canvas denoted by the rectangle whose corners are the four points (sx, sy), (sx+sw,
sy), (sx+sw, sy+sh), (sx, sy+sh), in canvas coordinate space units. Pixels outside the canvas must be returned as
transparent black. Pixels must be returned as non-premultiplied alpha values.
If any of the arguments to createImageData() p260 or getImageData() p260 are infinite or NaN, or if the
createImageData() p260 method is invoked with only one argument but that argument is null, the method must
instead raise a NOT_SUPPORTED_ERR p70 exception. If either the sw or sh arguments are zero, the method must
instead raise an INDEX_SIZE_ERR p70 exception.
ImageData p242 objects must be initialized so that their width attribute is set to w, the number of physical device
pixels per row in the image data, their height attribute is set to h, the number of rows in the image data, and their
260
data attribute is initialized to a CanvasPixelArray p242 object holding the image data. At least one pixel's worth of
image data must be returned.
The CanvasPixelArray p242 object provides ordered, indexed access to the color components of each pixel of the
image data. The data must be represented in left-to-right order, row by row top to bottom, starting with the top
left, with each pixel's red, green, blue, and alpha components being given in that order for each pixel. Each
component of each device pixel represented in this array must be in the range 0..255, representing the 8 bit value
for that component. The components must be assigned consecutive indices starting with 0 for the top left pixel's
red component.
The CanvasPixelArray p242 object thus represents h×w×4 integers. The length attribute of a
CanvasPixelArray p242 object must return this number.
The object's indices of the supported indexed properties are the numbers in the range 0 .. h×w×4-1.
When a CanvasPixelArray p242 object is indexed to retrieve an indexed property index, the value returned
must be the value of the indexth component in the array.
When a CanvasPixelArray p242 object is indexed to modify an indexed property index with value value, the
value of the indexth component in the array must be set to value.
Note: The width and height (w and h) might be different from the sw and sh arguments to the
above methods, e.g. if the canvas is backed by a high-resolution bitmap, or if the sw and sh
arguments are negative.
The putImageData(imagedata, dx, dy, dirtyX, dirtyY, dirtyWidth, dirtyHeight) method writes data
from ImageData p242 structures back to the canvas.
If any of the arguments to the method are infinite or NaN, the method must raise a NOT_SUPPORTED_ERR p70
exception.
If the first argument to the method is null or not an ImageData p242 object then the putImageData() p261 method
must raise a TYPE_MISMATCH_ERR p70 exception.
When the last four arguments are omitted, they must be assumed to have the values 0, 0, the width p260 member
of the imagedata structure, and the height p260 member of the imagedata structure, respectively.
When invoked with arguments that do not, per the last few paragraphs, cause an exception to be raised, the
putImageData() p261 method must act as follows:
1.
Let dxdevice be the x-coordinate of the device pixel in the underlying pixel data of the canvas
corresponding to the dx coordinate in the canvas coordinate space.
Let dydevice be the y-coordinate of the device pixel in the underlying pixel data of the canvas
corresponding to the dy coordinate in the canvas coordinate space.
2.
If dirtyWidth is negative, let dirtyX be dirtyX+dirtyWidth, and let dirtyWidth be equal to the absolute
magnitude of dirtyWidth.
If dirtyHeight is negative, let dirtyY be dirtyY+dirtyHeight, and let dirtyHeight be equal to the absolute
magnitude of dirtyHeight.
3.
If dirtyX is negative, let dirtyWidth be dirtyWidth+dirtyX, and let dirtyX be zero.
If dirtyY is negative, let dirtyHeight be dirtyHeight+dirtyY, and let dirtyY be zero.
4.
If dirtyX+dirtyWidth is greater than the width p260 attribute of the imagedata argument, let dirtyWidth be
the value of that width p260 attribute, minus the value of dirtyX.
If dirtyY+dirtyHeight is greater than the height p260 attribute of the imagedata argument, let dirtyHeight
be the value of that height p260 attribute, minus the value of dirtyY.
5.
If, after those changes, either dirtyWidth or dirtyHeight is negative or zero, stop these steps without
affecting the canvas.
6.
Otherwise, for all integer values of x and y where dirtyX ≤ x < dirtyX+dirtyWidth and
dirtyY ≤ y < dirtyY+dirtyHeight, copy the four channels of the pixel with coordinate (x, y) in the
imagedata data structure to the pixel with coordinate (dxdevice+x, dydevice+y) in the underlying pixel
data of the canvas.
The handling of pixel rounding when the specified coordinates do not exactly map to the device coordinate space
is not defined by this specification, except that the following must result in no visible changes to the rendering:
context.putImageData(context.getImageData(x, y, w, h), p, q);
261
...for any value of x, y, w, and h and where p is the smaller of x and the sum of x and w, and q is the smaller of y
and the sum of y and h; and except that the following two calls:
context.createImageData(w, h);
context.getImageData(0, 0, w, h);
...must return ImageData p242 objects with the same dimensions, for any value of w and h. In other words, while
user agents may round the arguments of these methods so that they map to device pixel boundaries, any
rounding performed must be performed consistently for all of the createImageData() p260 , getImageData() p260 and
putImageData() p261 operations.
Note: Due to the lossy nature of converting to and from premultiplied alpha color values,
pixels that have just been set using putImageData() p261 might be returned to an equivalent
getImageData() p260 as different values.
The current path, transformation matrix p243 , shadow attributes p249 , global alpha p244 , the clipping region p253 , and
global composition operator p244 must not affect the getImageData() p260 and putImageData() p261 methods.
The data returned by getImageData() p260 is at the resolution of the canvas backing store, which is likely to
not be one device pixel to each CSS pixel if the display used is a high resolution display.
In the following example, the script generates an ImageData p242 object so that it can draw onto it.
// canvas is a reference to a element
var context = canvas.getContext('2d');
// create a blank slate
var data = context.createImageData(canvas.width, canvas.height);
// create some plasma
FillPlasma(data, 'green'); // green plasma
// add a cloud to the plasma
AddCloud(data, data.width/2, data.height/2); // put a cloud in the middle
// paint the plasma+cloud on the canvas
context.putImageData(data, 0, 0);
// support methods
function FillPlasma(data, color) { ... }
function AddCloud(data, x, y) { ... }
Here is an example of using getImageData() p260 and putImageData() p261 to implement an edge detection
filter.
Edge detection demo
Please select a shape:
4.8.13.2 Processing model
If an img p186 element or an object p208 element representing an image has a usemap p268 attribute specified, user
agents must process it as follows:
1.
First, rules for parsing a hash-name reference p50 to a map p265 element must be followed. This will return
either an element (the map) or null.
2.
If that returned null, then abort these steps. The image is not associated with an image map after all.
3.
Otherwise, the user agent must collect all the area p266 elements that are descendants of the map. Let
those be the areas.
Having obtained the list of area p266 elements that form the image map (the areas), interactive user agents must
process the list in one of two ways.
If the user agent intends to show the text that the img p186 element represents, then it must use the following
steps.
Note: In user agents that do not support images, or that have images disabled, object p208
elements cannot represent images, and thus this section never applies (the fallback
content p92 is shown instead). The following steps therefore only apply to img p186 elements.
268
1.
Remove all the area p266 elements in areas that have no href p383 attribute.
2.
Remove all the area p266 elements in areas that have no alt p266 attribute, or whose alt p266 attribute's
value is the empty string, if there is another area p266 element in areas with the same value in the
href p383 attribute and with a non-empty alt p266 attribute.
3.
Each remaining area p266 element in areas represents a hyperlink p383 . Those hyperlinks should all be
made available to the user in a manner associated with the text of the img p186 .
In this context, user agents may represent area p266 and img p186 elements with no specified alt
attributes, or whose alt attributes are the empty string or some other non-visible text, in a user-agentdefined fashion intended to indicate the lack of suitable author-provided text.
If the user agent intends to show the image and allow interaction with the image to select hyperlinks, then the
image must be associated with a set of layered shapes, taken from the area p266 elements in areas, in reverse tree
order (so the last specified area p266 element in the map is the bottom-most shape, and the first element in the
map, in tree order, is the top-most shape).
Each area p266 element in areas must be processed as follows to obtain a shape to layer onto the image:
1.
Find the state that the element's shape p267 attribute represents.
2.
Use the rules for parsing a list of integers p38 to parse the element's coords p267 attribute, if it is present,
and let the result be the coords list. If the attribute is absent, let the coords list be the empty list.
3.
If the number of items in the coords list is less than the minimum number given for the area p266
element's current state, as per the following table, then the shape is empty; abort these steps.
State
Circle state
Minimum number of items
p267
Default state
p267
Polygon state p267
3
0
6
Rectangle state p267 4
4.
Check for excess items in the coords list as per the entry in the following list corresponding to the
shape p267 attribute's state:
p267
↪ Circle state
Drop any items in the list beyond the third.
p267
↪ Default state
Drop all items in the list.
p267
↪ Polygon state
Drop the last item if there's an odd number of items.
p267
↪ Rectangle state
Drop any items in the list beyond the fourth.
5.
If the shape p267 attribute represents the rectangle state p267 , and the first number in the list is numerically
less than the third number in the list, then swap those two numbers around.
6.
If the shape p267 attribute represents the rectangle state p267 , and the second number in the list is
numerically less than the fourth number in the list, then swap those two numbers around.
7.
If the shape p267 attribute represents the circle state p267 , and the third number in the list is less than or
equal to zero, then the shape is empty; abort these steps.
8.
Now, the shape represented by the element is the one described for the entry in the list below
corresponding to the state of the shape p267 attribute:
p267
↪ Circle state
Let x be the first number in coords, y be the second number, and r be the third number.
The shape is a circle whose center is x CSS pixels from the left edge of the image and x CSS
pixels from the top edge of the image, and whose radius is r pixels.
p267
↪ Default state
The shape is a rectangle that exactly covers the entire image.
p267
↪ Polygon state
Let xi be the (2i)th entry in coords, and yi be the (2i+1)th entry in coords (the first entry in
coords being the one with index 0).
Let the coordinates be (xi, yi), interpreted in CSS pixels measured from the top left of the
image, for all integer values of i from 0 to (N/2)-1, where N is the number of items in coords.
The shape is a polygon whose vertices are given by the coordinates, and whose interior is
established using the even-odd rule. [GRAPHICS] p701
269
p267
↪ Rectangle state
Let x1 be the first number in coords, y1 be the second number, x2 be the third number, and y2
be the fourth number.
The shape is a rectangle whose top-left corner is given by the coordinate (x1, y1) and whose
bottom right corner is given by the coordinate (x2, y2), those coordinates being interpreted as
CSS pixels from the top left corner of the image.
For historical reasons, the coordinates must be interpreted relative to the displayed image, even if it
stretched using CSS or the image element's width and height attributes.
Mouse clicks on an image associated with a set of layered shapes per the above algorithm must be dispatched to
the top-most shape covering the point that the pointing device indicated (if any), and then, must be dispatched
again (with a new Event p31 object) to the image element itself. User agents may also allow individual area p266
elements representing hyperlinks p383 to be selected and activated (e.g. using a keyboard); events from this are not
also propagated to the image.
Note: Because a map p265 element (and its area p266 elements) can be associated with multiple
img p186 and object p208 elements, it is possible for an area p266 element to correspond to multiple
focusable areas of the document.
Image maps are live p27 ; if the DOM is mutated, then the user agent must act as if it had rerun the algorithms for
image maps.
4.8.14 MathML
The math element from the MathML namespace p70 falls into the embedded content p92 , phrasing content p91 , and
flow content p91 categories for the purposes of the content models in this specification.
User agents must handle text other than inter-element whitespace p89 found in MathML elements whose content
models do not allow straight text by pretending for the purposes of MathML content models, layout, and rendering
that that text is actually wrapped in an mtext element in the MathML namespace p70 . (Such text is not, however,
conforming.)
User agents must act as if any MathML element whose contents does not match the element's content model was
replaced, for the purposes of MathML layout and rendering, by an merror element in the MathML namespace p70
containing some appropriate error message.
To enable authors to use MathML tools that only accept MathML in its XML form, interactive HTML user agents are
encouraged to provide a way to export any MathML fragment as an XML namespace-well-formed XML fragment.
The semantics of MathML elements are defined by the MathML specification and other relevant specifications.
[MATHML] p702
Here is an example of the use of MathML in an HTML document:
The quadratic formula
The quadratic formula
x
=
− b
±
b 2
−
4 a c
2 a
270
4.8.15 SVG
The svg element from the SVG namespace p70 falls into the embedded content p92 , phrasing content p91 , and flow
content p91 categories for the purposes of the content models in this specification.
To enable authors to use SVG tools that only accept SVG in its XML form, interactive HTML user agents are
encouraged to provide a way to export any SVG fragment as an XML namespace-well-formed XML fragment.
When the SVG foreignObject element contains elements from the HTML namespace p70 , such elements must all
be flow content p91 . [SVG] p704
The content model for title elements in the SVG namespace p70 inside HTML documents p71 is phrasing content p91 .
(This further constrains the requirements given in the SVG specification.)
The semantics of SVG elements are defined by the SVG specification and other relevant specifications. [SVG] p704
The SVG specification includes requirements regarding the handling of elements in the DOM that are not in the
SVG namespace, that are in SVG fragments, and that are not included in a foreignObject element. This
specification does not define any processing for elements in SVG fragments that are not in the HTML namespace;
they are considered neither conforming nor non-conforming from the perspective of this specification.
4.8.16 Dimension attributes
Author requirements: The width and height attributes on img p186 , iframe p199 , embed p205 , object p208 , video p213 ,
and, when their type p304 attribute is in the Image Button p321 state, input p303 elements may be specified to give the
dimensions of the visual content of the element (the width and height respectively, relative to the nominal
direction of the output medium), in CSS pixels. The attributes, if specified, must have values that are valid nonnegative integers p35 .
The specified dimensions given may differ from the dimensions specified in the resource itself, since the resource
may have a resolution that differs from the CSS pixel resolution. (On screens, CSS pixels have a resolution of
96ppi, but in general the CSS pixel resolution depends on the reading distance.) If both attributes are specified,
then one of the following statements must be true:
•
specified width - 0.5 ≤ specified height * target ratio ≤ specified width + 0.5
•
specified height - 0.5 ≤ specified width / target ratio ≤ specified height + 0.5
•
specified height = specified width = 0
The target ratio is the ratio of the intrinsic width to the intrinsic height in the resource. The specified width and
specified height are the values of the width p271 and height p271 attributes respectively.
The two attributes must be omitted if the resource in question does not have both an intrinsic width and an
intrinsic height.
If the two attributes are both zero, it indicates that the element is not intended for the user (e.g. it might be a part
of a service to count page views).
Note: The dimension attributes are not intended to be used to stretch the image.
User agent requirements: User agents are expected to use these attributes as hints for the rendering p650 .
The width and height IDL attributes on the iframe p199 , embed p205 , object p208 , and video p213 elements must
reflect p57 the respective content attributes of the same name.
4.9 Tabular data
4.9.1 The table element
Categories
Flow content p91 .
Contexts in which this element may be used:
Where flow content p91 is expected.
271
Content model:
In this order: optionally a caption p277 element, followed by either zero or more colgroup p278 elements,
followed optionally by a thead p280 element, followed optionally by a tfoot p280 element, followed by
either zero or more tbody p279 elements or one or more tr p281 elements, followed optionally by a
tfoot p280 element (but there can only be one tfoot p280 element child in total).
Content attributes:
Global attributes p82
summary p275 (but see prose)
DOM interface:
interface HTMLTableElement : HTMLElement {
attribute HTMLTableCaptionElement caption;
HTMLElement createCaption();
void deleteCaption();
attribute HTMLTableSectionElement tHead;
HTMLElement createTHead();
void deleteTHead();
attribute HTMLTableSectionElement tFoot;
HTMLElement createTFoot();
void deleteTFoot();
readonly attribute HTMLCollection tBodies;
HTMLElement createTBody();
readonly attribute HTMLCollection rows;
HTMLElement insertRow(in optional long index);
void deleteRow(in long index);
attribute DOMString summary;
};
The table p271 element represents p638 data with more than one dimension, in the form of a table p285 .
The table p271 element takes part in the table model p285 .
Tables must not be used as layout aids. Historically, some Web authors have misused tables in HTML as a way to
control their page layout. This usage is non-conforming, because tools attempting to extract tabular data from
such documents would obtain very confusing results. In particular, users of accessibility tools like screen readers
are likely to find it very difficult to navigate pages with tables used for layout.
Note: There are a variety of alternatives to using HTML tables for layout, primarily using CSS
positioning and the CSS table model.
User agents that do table analysis on arbitrary content are encouraged to find heuristics to determine which tables
actually contain data and which are merely being used for layout. This specification does not define a precise
heuristic.
Tables have rows and columns given by their descendants. A table must not have an empty row or column, as
described in the description of the table model p285 .
For tables that consist of more than just a grid of cells with headers in the first row and headers in the first column,
and for any table in general where the reader might have difficulty understanding the content, authors should
include explanatory information introducing the table. This information is useful for all users, but is especially
useful for users who cannot see the table, e.g. users of screen readers.
Such explanatory information should introduce the purpose of the table, outline its basic cell structure, highlight
any trends or patterns, and generally teach the user how to use the table.
For instance, the following table:
Characteristics with positive and
negative sides
Negative Characteristic Positive
Sad
Mood
Happy
Failing
Grade
Passing
...might benefit from a description explaining the way the table is laid out, something like "Characteristics
are given in the second column, with the negative side in the left column and the positive side in the right
column".
272
There are a variety of ways to include this information, such as:
In prose, surrounding the table
In the following table, characteristics are given in the second
column, with the negative side in the left column and the positive
side in the right column.
Characteristics with positive and negative sides
Negative
Characteristic
Positive
Sad
Mood
Happy
Failing
Grade
Passing
In the table's caption p277
Characteristics with positive and negative sides.
Characteristics are given in the second column, with the
negative side in the left column and the positive side in the right
column.
Negative
Characteristic
Positive
Sad
Mood
Happy
Failing
Grade
Passing
In the table's caption p277 , in a details p367 element
Characteristics with positive and negative sides.
Help
Characteristics are given in the second column, with the
negative side in the left column and the positive side in the right
column.
Negative
Characteristic
Positive
Sad
Mood
Happy
Failing
273
Grade
Passing
Next to the table, in the same figure p158
Characteristics with positive and negative sides
Characteristics are given in the second column, with the
negative side in the left column and the positive side in the right
column.
Negative
Characteristic
Positive
Sad
Mood
Happy
Failing
Grade
Passing
Next to the table, in a figure p158 's figcaption p159
Characteristics with positive and negative sides
Characteristics are given in the second column, with the
negative side in the left column and the positive side in the right
column.
Negative
Characteristic
Positive
Sad
Mood
Happy
Failing
Grade
Passing
Authors may also use other techniques, or combinations of the above techniques, as appropriate.
The best option, of course, rather than writing a description explaining the way the table is laid out, is to adjust
the table such that no explanation is needed.
In the case of the table used in the examples above, a simple rearrangement of the table so that the
headers are on the top and left sides removes the need for an explanation as well as removing the need for
the use of headers p284 attributes:
Characteristics with positive and negative sides
Characteristic
Negative
Positive
274
Mood
Sad
Happy
Grade
Failing
Passing
The summary attribute on table p271 elements was suggested in earlier versions of the language as a technique for
providing explanatory text for complex tables for users of screen readers. One of the techniques p272 described
above should be used instead.
Note: In particular, authors are encouraged to consider whether their explanatory text for
tables is likely to be useful to the visually impaired: if their text would not be useful, then it is
best to not include a summary p275 attribute. Similarly, if their explanatory text could help
someone who is not visually impaired, e.g. someone who is seeing the table for the first time,
then the text would be more useful before the table or in the caption p277 . For example,
describing the conclusions of the data in a table is useful to everyone; explaining how to read
the table, if not obvious from the headers alone, is useful to everyone; describing the
structure of the table, if it is easy to grasp visually, may not be useful to everyone, but it
might also not be useful to users who can quickly navigate the table with an accessibility tool.
If a table p271 element has a summary p275 attribute, the user agent may report the contents of that attribute to the
user.
This box is non-normative. Implementation requirements are given below this box.
table . caption
p276
[ = value ]
Returns the table's caption p277 element.
Can be set, to replace the caption p277 element. If the new value is not a caption p277 element, throws a
HIERARCHY_REQUEST_ERR p70 exception.
caption = table . createCaption p276 ()
Ensures the table has a caption p277 element, and returns it.
table . deleteCaption p276 ()
Ensures the table does not have a caption p277 element.
table . tHead p276 [ = value ]
Returns the table's thead p280 element.
Can be set, to replace the thead p280 element. If the new value is not a thead p280 element, throws a
HIERARCHY_REQUEST_ERR p70 exception.
thead = table . createTHead p276 ()
Ensures the table has a thead p280 element, and returns it.
table . deleteTHead p276 ()
Ensures the table does not have a thead p280 element.
table . tFoot p276 [ = value ]
Returns the table's tfoot p280 element.
Can be set, to replace the tfoot p280 element. If the new value is not a tfoot p280 element, throws a
HIERARCHY_REQUEST_ERR p70 exception.
tfoot = table . createTFoot p276 ()
Ensures the table has a tfoot p280 element, and returns it.
table . deleteTFoot p276 ()
Ensures the table does not have a tfoot p280 element.
table . tBodies p276
Returns an HTMLCollection p59 of the tbody p279 elements of the table.
275
tbody = table . createTBody p277 ()
Creates a tbody p279 element, inserts it into the table, and returns it.
table . rows p277
Returns an HTMLCollection p59 of the tr p281 elements of the table.
tr = table . insertRow p277 (index)
Creates a tr p281 element, along with a tbody p279 if required, inserts them into the table at the position
given by the argument, and returns the tr p281 .
The position is relative to the rows in the table. The index −1 is equivalent to inserting at the end of
the table.
If the given position is less than −1 or greater than the number of rows, throws an INDEX_SIZE_ERR p70
exception.
table . deleteRow p277 (index)
Removes the tr p281 element with the given position in the table.
The position is relative to the rows in the table. The index −1 is equivalent to deleting the last row of
the table.
If the given position is less than −1 or greater than the index of the last row, or if there are no rows,
throws an INDEX_SIZE_ERR p70 exception.
The caption IDL attribute must return, on getting, the first caption p277 element child of the table p271 element, if
any, or null otherwise. On setting, if the new value is a caption p277 element, the first caption p277 element child of
the table p271 element, if any, must be removed, and the new value must be inserted as the first node of the
table p271 element. If the new value is not a caption p277 element, then a HIERARCHY_REQUEST_ERR p70 DOM
exception must be raised instead.
The createCaption() method must return the first caption p277 element child of the table p271 element, if any;
otherwise a new caption p277 element must be created, inserted as the first node of the table p271 element, and
then returned.
The deleteCaption() method must remove the first caption p277 element child of the table p271 element, if any.
The tHead IDL attribute must return, on getting, the first thead p280 element child of the table p271 element, if any,
or null otherwise. On setting, if the new value is a thead p280 element, the first thead p280 element child of the
table p271 element, if any, must be removed, and the new value must be inserted immediately before the first
element in the table p271 element that is neither a caption p277 element nor a colgroup p278 element, if any, or at
the end of the table if there are no such elements. If the new value is not a thead p280 element, then a
HIERARCHY_REQUEST_ERR p70 DOM exception must be raised instead.
The createTHead() method must return the first thead p280 element child of the table p271 element, if any;
otherwise a new thead p280 element must be created and inserted immediately before the first element in the
table p271 element that is neither a caption p277 element nor a colgroup p278 element, if any, or at the end of the
table if there are no such elements, and then that new element must be returned.
The deleteTHead() method must remove the first thead p280 element child of the table p271 element, if any.
The tFoot IDL attribute must return, on getting, the first tfoot p280 element child of the table p271 element, if any,
or null otherwise. On setting, if the new value is a tfoot p280 element, the first tfoot p280 element child of the
table p271 element, if any, must be removed, and the new value must be inserted immediately before the first
element in the table p271 element that is neither a caption p277 element, a colgroup p278 element, nor a thead p280
element, if any, or at the end of the table if there are no such elements. If the new value is not a tfoot p280
element, then a HIERARCHY_REQUEST_ERR p70 DOM exception must be raised instead.
The createTFoot() method must return the first tfoot p280 element child of the table p271 element, if any;
otherwise a new tfoot p280 element must be created and inserted immediately before the first element in the
table p271 element that is neither a caption p277 element, a colgroup p278 element, nor a thead p280 element, if any,
or at the end of the table if there are no such elements, and then that new element must be returned.
The deleteTFoot() method must remove the first tfoot p280 element child of the table p271 element, if any.
The tBodies attribute must return an HTMLCollection p59 rooted at the table p271 node, whose filter matches only
tbody p279 elements that are children of the table p271 element.
276
The createTBody() method must create a new tbody p279 element, insert it immediately after the last tbody p279
element in the table p271 element, if any, or at the end of the table p271 element if the table p271 element has no
tbody p279 element children, and then must return the new tbody p279 element.
The rows attribute must return an HTMLCollection p59 rooted at the table p271 node, whose filter matches only
tr p281 elements that are either children of the table p271 element, or children of thead p280 , tbody p279 , or tfoot p280
elements that are themselves children of the table p271 element. The elements in the collection must be ordered
such that those elements whose parent is a thead p280 are included first, in tree order, followed by those elements
whose parent is either a table p271 or tbody p279 element, again in tree order, followed finally by those elements
whose parent is a tfoot p280 element, still in tree order.
The behavior of the insertRow(index) method depends on the state of the table. When it is called, the method
must act as required by the first item in the following list of conditions that describes the state of the table and the
index argument:
p277
collection:
↪ If index is less than −1 or greater than the number of elements in rows
The method must raise an INDEX_SIZE_ERR p70 exception.
p277
collection has zero elements in it, and the table p271 has no tbody p279 elements in it:
↪ If the rows
The method must create a tbody p279 element, then create a tr p281 element, then append the tr p281
element to the tbody p279 element, then append the tbody p279 element to the table p271 element, and
finally return the tr p281 element.
p277
collection has zero elements in it:
↪ If the rows
The method must create a tr p281 element, append it to the last tbody p279 element in the table, and return
the tr p281 element.
p277
collection:
↪ If index is missing, equal to −1, or equal to the number of items in rows
The method must create a tr p281 element, and append it to the parent of the last tr p281 element in the
rows p277 collection. Then, the newly created tr p281 element must be returned.
↪ Otherwise:
The method must create a tr p281 element, insert it immediately before the indexth tr p281 element in the
rows p277 collection, in the same parent, and finally must return the newly created tr p281 element.
When the deleteRow(index) method is called, the user agent must run the following steps:
1.
If index is equal to −1, then index must be set to the number if items in the rows p277 collection, minus
one.
2.
Now, if index is less than zero, or greater than or equal to the number of elements in the rows p277
collection, the method must instead raise an INDEX_SIZE_ERR p70 exception, and these steps must be
aborted.
3.
Otherwise, the method must remove the indexth element in the rows p277 collection from its parent.
The summary IDL attribute must reflect p57 the content attribute of the same name.
4.9.2 The caption element
Categories
None.
Contexts in which this element may be used:
As the first element child of a table p271 element.
Content model:
Flow content p91 , but with no descendant table p271 elements.
Content attributes:
Global attributes p82
DOM interface:
interface HTMLTableCaptionElement : HTMLElement {};
The caption p277 element represents p638 the title of the table p271 that is its parent, if it has a parent and that is a
table p271 element.
The caption p277 element takes part in the table model p285 .
277
When a table p271 element is the only content in a figure p158 element other than the figcaption p159 , the
caption p277 element should be omitted in favor of the figcaption p159 .
A caption can introduce context for a table, making it significantly easier to understand.
Consider, for instance, the following table:
1
2
3
4
5
6
1
2
3
4
5
6
7
2
3
4
5
6
7
8
3
4
5
6
7
8
9
4 5 6
5 6 7
6 7 8
7 8 9
8 9 10
9 1011
101112
In the abstract, this table is not clear. However, with a caption giving the table's number (for reference in
the main prose) and explaining its use, it makes more sense:
Table 1.
This table shows the total score obtained from rolling two
six-sided dice. The first row represents the value of the first die,
the first column the value of the second die. The total is given in
the cell that corresponds to the values of the two dice.
This provides the user with more context:
Table 1.
This table shows the total score obtained from rolling two
six-sided dice. The first row represents the value of the first
die, the first column the value of the second die. The total
is given in the cell that corresponds to the values of the
two dice.
1
2
3
4
5
6
1
2
3
4
5
6
7
2
3
4
5
6
7
8
3
4
5
6
7
8
9
4 5 6
5 6 7
6 7 8
7 8 9
8 9 10
9 1011
101112
4.9.3 The colgroup element
Categories
None.
Contexts in which this element may be used:
As a child of a table p271 element, after any caption p277 elements and before any thead p280 , tbody p279 ,
tfoot p280 , and tr p281 elements.
Content model:
If the span p278 attribute is present: Empty.
If the span p278 attribute is absent: Zero or more col p279 elements.
Content attributes:
Global attributes p82
span p278
DOM interface:
interface HTMLTableColElement : HTMLElement {
attribute unsigned long span;
};
The colgroup p278 element represents p638 a group p285 of one or more columns p285 in the table p271 that is its parent,
if it has a parent and that is a table p271 element.
If the colgroup p278 element contains no col p279 elements, then the element may have a span content attribute
specified, whose value must be a valid non-negative integer p35 greater than zero.
The colgroup p278 element and its span p278 attribute take part in the table model p285 .
278
The span IDL attribute must reflect p57 the content attribute of the same name. The value must be limited to only
non-negative numbers greater than zero p58 .
4.9.4 The col element
Categories
None.
Contexts in which this element may be used:
As a child of a colgroup p278 element that doesn't have a span p279 attribute.
Content model:
Empty.
Content attributes:
Global attributes p82
span p279
DOM interface:
HTMLTableColElement p278 , same as for colgroup p278 elements. This interface defines one member,
span p279 .
If a col p279 element has a parent and that is a colgroup p278 element that itself has a parent that is a table p271
element, then the col p279 element represents p638 one or more columns p285 in the column group p285 represented by
that colgroup p278 .
The element may have a span content attribute specified, whose value must be a valid non-negative integer p35
greater than zero.
The col p279 element and its span p279 attribute take part in the table model p285 .
The span IDL attribute must reflect p57 the content attribute of the same name. The value must be limited to only
non-negative numbers greater than zero p58 .
4.9.5 The tbody element
Categories
None.
Contexts in which this element may be used:
As a child of a table p271 element, after any caption p277 , colgroup p278 , and thead p280 elements, but only
if there are no tr p281 elements that are children of the table p271 element.
Content model:
Zero or more tr p281 elements
Content attributes:
Global attributes p82
DOM interface:
interface HTMLTableSectionElement : HTMLElement {
readonly attribute HTMLCollection rows;
HTMLElement insertRow(in optional long index);
void deleteRow(in long index);
};
The HTMLTableSectionElement p279 interface is also used for thead p280 and tfoot p280 elements.
The tbody p279 element represents p638 a block p285 of rows p285 that consist of a body of data for the parent table p271
element, if the tbody p279 element has a parent and it is a table p271 .
The tbody p279 element takes part in the table model p285 .
This box is non-normative. Implementation requirements are given below this box.
tbody . rows
p280
Returns an HTMLCollection p59 of the tr p281 elements of the table section.
279
tr = tbody . insertRow p280 ( [ index ] )
Creates a tr p281 element, inserts it into the table section at the position given by the argument, and
returns the tr p281 .
The position is relative to the rows in the table section. The index −1, which is the default if the
argument is omitted, is equivalent to inserting at the end of the table section.
If the given position is less than −1 or greater than the number of rows, throws an INDEX_SIZE_ERR p70
exception.
tbody . deleteRow p280 (index)
Removes the tr p281 element with the given position in the table section.
The position is relative to the rows in the table section. The index −1 is equivalent to deleting the last
row of the table section.
If the given position is less than −1 or greater than the index of the last row, or if there are no rows,
throws an INDEX_SIZE_ERR p70 exception.
The rows attribute must return an HTMLCollection p59 rooted at the element, whose filter matches only tr p281
elements that are children of the element.
The insertRow(index) method must, when invoked on an element table section, act as follows:
If index is less than −1 or greater than the number of elements in the rows p280 collection, the method must raise
an INDEX_SIZE_ERR p70 exception.
If index is missing, equal to −1, or equal to the number of items in the rows p280 collection, the method must create
a tr p281 element, append it to the element table section, and return the newly created tr p281 element.
Otherwise, the method must create a tr p281 element, insert it as a child of the table section element, immediately
before the indexth tr p281 element in the rows p280 collection, and finally must return the newly created tr p281
element.
The deleteRow(index) method must remove the indexth element in the rows p280 collection from its parent. If
index is less than zero or greater than or equal to the number of elements in the rows p280 collection, the method
must instead raise an INDEX_SIZE_ERR p70 exception.
4.9.6 The thead element
Categories
None.
Contexts in which this element may be used:
As a child of a table p271 element, after any caption p277 , and colgroup p278 elements and before any
tbody p279 , tfoot p280 , and tr p281 elements, but only if there are no other thead p280 elements that are
children of the table p271 element.
Content model:
Zero or more tr p281 elements
Content attributes:
Global attributes p82
DOM interface:
HTMLTableSectionElement p279 , as defined for tbody p279 elements.
The thead p280 element represents p638 the block p285 of rows p285 that consist of the column labels (headers) for the
parent table p271 element, if the thead p280 element has a parent and it is a table p271 .
The thead p280 element takes part in the table model p285 .
4.9.7 The tfoot element
Categories
None.
280
Contexts in which this element may be used:
As a child of a table p271 element, after any caption p277 , colgroup p278 , and thead p280 elements and
before any tbody p279 and tr p281 elements, but only if there are no other tfoot p280 elements that are
children of the table p271 element.
As a child of a table p271 element, after any caption p277 , colgroup p278 , thead p280 , tbody p279 , and tr p281
elements, but only if there are no other tfoot p280 elements that are children of the table p271 element.
Content model:
Zero or more tr p281 elements
Content attributes:
Global attributes p82
DOM interface:
HTMLTableSectionElement p279 , as defined for tbody p279 elements.
The tfoot p280 element represents p638 the block p285 of rows p285 that consist of the column summaries (footers) for
the parent table p271 element, if the tfoot p280 element has a parent and it is a table p271 .
The tfoot p280 element takes part in the table model p285 .
4.9.8 The tr element
Categories
None.
Contexts in which this element may be used:
As a child of a thead p280
As a child of a tbody p279
As a child of a tfoot p280
As a child of a table p271
if there are no tbody p279
element.
element.
element.
element, after any caption p277 , colgroup p278 , and thead p280 elements, but only
elements that are children of the table p271 element.
Content model:
When the parent node is a thead p280 element: Zero or more th p283 elements
Otherwise: Zero or more td p282 or th p283 elements
Content attributes:
Global attributes p82
DOM interface:
interface HTMLTableRowElement : HTMLElement {
readonly attribute long rowIndex;
readonly attribute long sectionRowIndex;
readonly attribute HTMLCollection cells;
HTMLElement insertCell(in optional long index);
void deleteCell(in long index);
};
The tr p281 element represents p638 a row p285 of cells p285 in a table p285 .
The tr p281 element takes part in the table model p285 .
This box is non-normative. Implementation requirements are given below this box.
tr . rowIndex p282
Returns the position of the row in the table's rows p277 list.
Returns −1 if the element isn't in a table.
tr . sectionRowIndex p282
Returns the position of the row in the table section's rows p280 list.
Returns −1 if the element isn't in a table section.
281
tr . cells p282
Returns an HTMLCollection p59 of the td p282 and th p283 elements of the row.
cell = tr . insertCell p282 ( [ index ] )
Creates a td p282 element, inserts it into the table row at the position given by the argument, and
returns the td p282 .
The position is relative to the cells in the row. The index −1, which is the default if the argument is
omitted, is equivalent to inserting at the end of the row.
If the given position is less than −1 or greater than the number of cells, throws an INDEX_SIZE_ERR p70
exception.
tr . deleteCell p282 (index)
Removes the td p282 or th p283 element with the given position in the row.
The position is relative to the cells in the row. The index −1 is equivalent to deleting the last cell of the
row.
If the given position is less than −1 or greater than the index of the last cell, or if there are no cells,
throws an INDEX_SIZE_ERR p70 exception.
The rowIndex attribute must, if the element has a parent table p271 element, or a parent tbody p279 , thead p280 , or
tfoot p280 element and a grandparent table p271 element, return the index of the tr p281 element in that table p271
element's rows p277 collection. If there is no such table p271 element, then the attribute must return −1.
The sectionRowIndex attribute must, if the element has a parent table p271 , tbody p279 , thead p280 , or tfoot p280
element, return the index of the tr p281 element in the parent element's rows collection (for tables, that's the
HTMLTableElement.rows p277 collection; for table sections, that's the HTMLTableRowElement.rows p280 collection). If
there is no such parent element, then the attribute must return −1.
The cells attribute must return an HTMLCollection p59 rooted at the tr p281 element, whose filter matches only
td p282 and th p283 elements that are children of the tr p281 element.
The insertCell(index) method must act as follows:
If index is less than −1 or greater than the number of elements in the cells p282 collection, the method must raise
an INDEX_SIZE_ERR p70 exception.
If index is missing, equal to −1, or equal to the number of items in cells p282 collection, the method must create a
td p282 element, append it to the tr p281 element, and return the newly created td p282 element.
Otherwise, the method must create a td p282 element, insert it as a child of the tr p281 element, immediately before
the indexth td p282 or th p283 element in the cells p282 collection, and finally must return the newly created td p282
element.
The deleteCell(index) method must remove the indexth element in the cells p282 collection from its parent. If
index is less than zero or greater than or equal to the number of elements in the cells p282 collection, the method
must instead raise an INDEX_SIZE_ERR p70 exception.
4.9.9 The td element
Categories
Sectioning root p144 .
Contexts in which this element may be used:
As a child of a tr p281 element.
Content model:
Flow content p91 .
Content attributes:
Global attributes p82
colspan p284
rowspan p284
headers p284
DOM interface:
interface HTMLTableDataCellElement : HTMLTableCellElement {};
282
The td p282 element represents p638 a data cell p285 in a table.
The td p282 element and its colspan p284 , rowspan p284 , and headers p284 attributes take part in the table model p285 .
4.9.10 The th element
Categories
None.
Contexts in which this element may be used:
As a child of a tr p281 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
colspan p284
rowspan p284
headers p284
scope p283
DOM interface:
interface HTMLTableHeaderCellElement : HTMLTableCellElement {
attribute DOMString scope;
};
The th p283 element represents p638 a header cell p285 in a table.
The th p283 element may have a scope content attribute specified. The scope p283 attribute is an enumerated
attribute p34 with five states, four of which have explicit keywords:
The row keyword, which maps to the row state
The row state means the header cell applies to some of the subsequent cells in the same row(s).
The col keyword, which maps to the column state
The column state means the header cell applies to some of the subsequent cells in the same column(s).
The rowgroup keyword, which maps to the row group state
The row group state means the header cell applies to all the remaining cells in the row group. A th p283
element's scope p283 attribute must not be in the row group p283 state if the element is not anchored in a row
group p285 .
The colgroup keyword, which maps to the column group state
The column group state means the header cell applies to all the remaining cells in the column group. A th p283
element's scope p283 attribute must not be in the column group p283 state if the element is not anchored in a
column group p285 .
The auto state
The auto state makes the header cell apply to a set of cells selected based on context.
The scope p283 attribute's missing value default is the auto state.
The th p283 element and its colspan p284 , rowspan p284 , headers p284 , and scope p283 attributes take part in the table
model p285 .
The scope IDL attribute must reflect p57 the content attribute of the same name.
The following example shows how the scope p283 attribute's rowgroup p283 value affects which data cells a
header cell applies to.
Here is a markup fragment showing a table:
ID Measurement Average Maximum
Cats
93 Legs 3.5 4
10 Tails 1 1
English speakers
283
32 Legs 2.67 4
35 Tails 0.33 1
This would result in the following table:
ID
Measurement
Average Maximum
Cats
93 Legs
3.5
4
10 Tails
1
1
32 Legs
2.67
4
35 Tails
0.33
1
English speakers
The headers in the first row all apply directly down to the rows in their column.
The headers with the explicit scope p283 attributes apply to all the cells in their row group other than the cells
in the first column.
The remaining headers apply just to the cells to the right of them.
4.9.11 Attributes common to td p282 and th p283 elements
The td p282 and th p283 elements may have a colspan content attribute specified, whose value must be a valid nonnegative integer p35 greater than zero.
The td p282 and th p283 elements may also have a rowspan content attribute specified, whose value must be a valid
non-negative integer p35 .
These attributes give the number of columns and rows respectively that the cell is to span. These attributes must
not be used to overlap cells, as described in the description of the table model p285 .
The td p282 and th p283 element may have a headers content attribute specified. The headers p284 attribute, if
specified, must contain a string consisting of an unordered set of unique space-separated tokens p49 , each of which
must have the value of an ID of a th p283 element taking part in the same table p285 as the td p282 or th p283 element
(as defined by the table model p285 ).
A th p283 element with ID id is said to be directly targeted by all td p282 and th p283 elements in the same table p285
that have headers p284 attributes whose values include as one of their tokens the ID id. A th p283 element A is said to
be targeted by a th p283 or td p282 element B if either A is directly targeted by B or if there exists an element C that
is itself targeted by the element B and A is directly targeted by C.
A th p283 element must not be targeted by itself.
The colspan p284 , rowspan p284 , and headers p284 attributes take part in the table model p285 .
284
The td p282 and th p283 elements implement interfaces that inherit from the HTMLTableCellElement p285 interface:
interface HTMLTableCellElement : HTMLElement {
attribute unsigned long colSpan;
attribute unsigned long rowSpan;
[PutForwards=value] readonly attribute DOMSettableTokenList headers;
readonly attribute long cellIndex;
};
This box is non-normative. Implementation requirements are given below this box.
cell . cellIndex
p285
Returns the position of the cell in the row's cells p282 list. This does not necessarily correspond to the
x-position of the cell in the table, since earlier cells might cover multiple rows or columns.
Returns 0 if the element isn't in a row.
The colSpan IDL attribute must reflect p57 the content attribute of the same name. The value must be limited to
only non-negative numbers greater than zero p58 .
The rowSpan IDL attribute must reflect p57 the content attribute of the same name. Its default value, which must be
used if parsing the attribute as a non-negative integer p35 returns an error, is 1.
The headers IDL attribute must reflect p57 the content attribute of the same name.
The cellIndex IDL attribute must, if the element has a parent tr p281 element, return the index of the cell's
element in the parent element's cells p282 collection. If there is no such parent element, then the attribute must
return 0.
4.9.12 Processing model
The various table elements and their content attributes together define the table model.
A table consists of cells aligned on a two-dimensional grid of slots with coordinates (x, y). The grid is finite, and is
either empty or has one or more slots. If the grid has one or more slots, then the x coordinates are always in the
range 0 ≤ x < xwidth, and the y coordinates are always in the range 0 ≤ y < yheight. If one or both of xwidth and
yheight are zero, then the table is empty (has no slots). Tables correspond to table p271 elements.
A cell is a set of slots anchored at a slot (cellx, celly), and with a particular width and height such that the cell
covers all the slots with coordinates (x, y) where cellx ≤ x < cellx+width and celly ≤ y < celly+height. Cells can
either be data cells or header cells. Data cells correspond to td p282 elements, and header cells correspond to th p283
elements. Cells of both types can have zero or more associated header cells.
It is possible, in certain error cases, for two cells to occupy the same slot.
A row is a complete set of slots from x=0 to x=xwidth-1, for a particular value of y. Rows correspond to tr p281
elements.
A column is a complete set of slots from y=0 to y=yheight-1, for a particular value of x. Columns can correspond
to col p279 elements. In the absence of col p279 elements, columns are implied.
A row group is a set of rows p285 anchored at a slot (0, groupy) with a particular height such that the row group
covers all the slots with coordinates (x, y) where 0 ≤ x < xwidth and groupy ≤ y < groupy+height. Row groups
correspond to tbody p279 , thead p280 , and tfoot p280 elements. Not every row is necessarily in a row group.
A column group is a set of columns p285 anchored at a slot (groupx, 0) with a particular width such that the
column group covers all the slots with coordinates (x, y) where groupx ≤ x < groupx+width and 0 ≤ y < yheight.
Column groups correspond to colgroup p278 elements. Not every column is necessarily in a column group.
Row groups p285 cannot overlap each other. Similarly, column groups p285 cannot overlap each other.
A cell p285 cannot cover slots that are from two or more row groups p285 . It is, however, possible for a cell to be in
multiple column groups p285 . All the slots that form part of one cell are part of zero or one row groups p285 and zero
or more column groups p285 .
In addition to cells p285 , columns p285 , rows p285 , row groups p285 , and column groups p285 , tables p285 can have a
caption p277 element associated with them. This gives the table a heading, or legend.
A table model error is an error with the data represented by table p271 elements and their descendants.
Documents must not have table model errors.
285
4.9.12.1 Forming a table
To determine which elements correspond to which slots in a table p285 associated with a table p271 element, to
determine the dimensions of the table (xwidth and yheight), and to determine if there are any table model
errors p285 , user agents must use the following algorithm:
1.
Let xwidth be zero.
2.
Let yheight be zero.
3.
Let pending tfoot p280 elements be a list of tfoot p280 elements, initially empty.
4.
Let the table be the table p285 represented by the table p271 element. The xwidth and yheight variables give
the table's dimensions. The table is initially empty.
5.
If the table p271 element has no children elements, then return the table (which will be empty), and abort
these steps.
6.
Associate the first caption p277 element child of the table p271 element with the table. If there are no such
children, then it has no associated caption p277 element.
7.
Let the current element be the first element child of the table p271 element.
If a step in this algorithm ever requires the current element to be advanced to the next child of the
table when there is no such next child, then the user agent must jump to the step labeled end, near the
end of this algorithm.
8.
While the current element is not one of the following elements, advance p286 the current element to the
next child of the table p271 :
•
•
•
•
•
9.
colgroup p278
thead p280
tbody p279
tfoot p280
tr p281
If the current element is a colgroup p278 , follow these substeps:
1.
Column groups: Process the current element according to the appropriate case below:
p279
element children
↪ If the current element has any col
Follow these steps:
1.
Let xstart have the value of xwidth.
2.
Let the current column be the first col p279 element child of the
colgroup p278 element.
3.
Columns: If the current column col p279 element has a span p279 attribute,
then parse its value using the rules for parsing non-negative integers p35 .
If the result of parsing the value is not an error or zero, then let span be
that value.
Otherwise, if the col p279 element has no span p279 attribute, or if trying to
parse the attribute's value resulted in an error or zero, then let span be 1.
4.
Increase xwidth by span.
5.
Let the last span columns p285 in the table correspond to the current column
col p279 element.
6.
If current column is not the last col p279 element child of the colgroup p278
element, then let the current column be the next col p279 element child of
the colgroup p278 element, and return to the step labeled columns.
7.
Let all the last columns p285 in the table from x=xstart to x=xwidth-1 form a
new column group p285 , anchored at the slot (xstart, 0), with width
xwidth-xstart, corresponding to the colgroup p278 element.
p279
element children
↪ If the current element has no col
1.
286
If the colgroup p278 element has a span p278 attribute, then parse its value
using the rules for parsing non-negative integers p35 .
If the result of parsing the value is not an error or zero, then let span be
that value.
Otherwise, if the colgroup p278 element has no span p278 attribute, or if
trying to parse the attribute's value resulted in an error or zero, then let
span be 1.
2.
Increase xwidth by span.
3.
Let the last span columns p285 in the table form a new column group p285 ,
anchored at the slot (xwidth-span, 0), with width span, corresponding to the
colgroup p278 element.
2.
Advance p286 the current element to the next child of the table p271 .
3.
While the current element is not one of the following elements, advance p286 the current
element to the next child of the table p271 :
•
•
•
•
•
4.
colgroup p278
thead p280
tbody p279
tfoot p280
tr p281
If the current element is a colgroup p278 element, jump to the step labeled column groups
above.
10.
Let ycurrent be zero.
11.
Let the list of downward-growing cells be an empty list.
12.
Rows: While the current element is not one of the following elements, advance p286 the current element
to the next child of the table p271 :
•
•
•
•
thead p280
tbody p279
tfoot p280
tr p281
13.
If the current element is a tr p281 , then run the algorithm for processing rows p288 , advance p286 the current
element to the next child of the table p271 , and return to the step labeled rows.
14.
Run the algorithm for ending a row group p288 .
15.
If the current element is a tfoot p280 , then add that element to the list of pending tfoot p280 elements,
advance p286 the current element to the next child of the table p271 , and return to the step labeled rows.
16.
The current element is either a thead p280 or a tbody p279 .
Run the algorithm for processing row groups p287 .
17.
Advance p286 the current element to the next child of the table p271 .
18.
Return to the step labeled rows.
19.
End: For each tfoot p280 element in the list of pending tfoot p280 elements, in tree order, run the
algorithm for processing row groups p287 .
20.
If there exists a row p285 or column p285 in the table containing only slots p285 that do not have a cell p285
anchored to them, then this is a table model error p285 .
21.
Return the table.
The algorithm for processing row groups, which is invoked by the set of steps above for processing thead p280 ,
tbody p279 , and tfoot p280 elements, is:
1.
Let ystart have the value of yheight.
2.
For each tr p281 element that is a child of the element being processed, in tree order, run the algorithm
for processing rows p288 .
3.
If yheight > ystart, then let all the last rows p285 in the table from y=ystart to y=yheight-1 form a new row
group p285 , anchored at the slot with coordinate (0, ystart), with height yheight-ystart, corresponding to the
element being processed.
4.
Run the algorithm for ending a row group p288 .
287
The algorithm for ending a row group, which is invoked by the set of steps above when starting and ending a
block of rows, is:
1.
2.
While ycurrent is less than yheight, follow these steps:
1.
Run the algorithm for growing downward-growing cells p288 .
2.
Increase ycurrent by 1.
Empty the list of downward-growing cells.
The algorithm for processing rows, which is invoked by the set of steps above for processing tr p281 elements,
is:
1.
If yheight is equal to ycurrent, then increase yheight by 1. (ycurrent is never greater than yheight.)
2.
Let xcurrent be 0.
3.
Run the algorithm for growing downward-growing cells p288 .
4.
If the tr p281 element being processed has no td p282 or th p283 element children, then increase ycurrent by
1, abort this set of steps, and return to the algorithm above.
5.
Let current cell be the first td p282 or th p283 element in the tr p281 element being processed.
6.
Cells: While xcurrent is less than xwidth and the slot with coordinate (xcurrent, ycurrent) already has a cell
assigned to it, increase xcurrent by 1.
7.
If xcurrent is equal to xwidth, increase xwidth by 1. (xcurrent is never greater than xwidth.)
8.
If the current cell has a colspan p284 attribute, then parse that attribute's value p35 , and let colspan be the
result.
If parsing that value failed, or returned zero, or if the attribute is absent, then let colspan be 1, instead.
9.
If the current cell has a rowspan p284 attribute, then parse that attribute's value p35 , and let rowspan be
the result.
If parsing that value failed or if the attribute is absent, then let rowspan be 1, instead.
10.
If rowspan is zero, then let cell grows downward be true, and set rowspan to 1. Otherwise, let cell grows
downward be false.
11.
If xwidth < xcurrent+colspan, then let xwidth be xcurrent+colspan.
12.
If yheight < ycurrent+rowspan, then let yheight be ycurrent+rowspan.
13.
Let the slots with coordinates (x, y) such that xcurrent ≤ x < xcurrent+colspan and
ycurrent ≤ y < ycurrent+rowspan be covered by a new cell p285 c, anchored at (xcurrent, ycurrent), which has
width colspan and height rowspan, corresponding to the current cell element.
If the current cell element is a th p283 element, let this new cell c be a header cell; otherwise, let it be a
data cell.
To establish which header cells apply to the current cell element, use the algorithm for assigning header
cells p289 described in the next section.
If any of the slots involved already had a cell p285 covering them, then this is a table model error p285 .
Those slots now have two cells overlapping.
14.
If cell grows downward is true, then add the tuple {c, xcurrent, colspan} to the list of downward-growing
cells.
15.
Increase xcurrent by colspan.
16.
If current cell is the last td p282 or th p283 element in the tr p281 element being processed, then increase
ycurrent by 1, abort this set of steps, and return to the algorithm above.
17.
Let current cell be the next td p282 or th p283 element in the tr p281 element being processed.
18.
Return to the step labelled cells.
When the algorithms above require the user agent to run the algorithm for growing downward-growing cells,
the user agent must, for each {cell, cellx, width} tuple in the list of downward-growing cells, if any, extend the
cell p285 cell so that it also covers the slots with coordinates (x, ycurrent), where cellx ≤ x < cellx+width.
288
4.9.12.2 Forming relationships between data cells and header cells
Each cell can be assigned zero or more header cells. The algorithm for assigning header cells to a cell
principal cell is as follows.
1.
Let header list be an empty list of cells.
2.
Let (principalx, principaly) be the coordinate of the slot to which the principal cell is anchored.
3.↪ If the principal cell has a headers p284 attribute specified
1.
Take the value of the principal cell's headers p284 attribute and split it on spaces p49 ,
letting id list be the list of tokens obtained.
2.
For each token in the id list, if the first element in the Document p31 with an ID equal to
the token is a cell in the same table p285 , and that cell is not the principal cell, then
add that cell to header list.
p284
attribute specified
↪ If principal cell does not have a headers
1.
Let principalwidth be the width of the principal cell.
2.
Let principalheight be the height of the principal cell.
3.
For each value of y from principaly to principaly+principalheight-1, run the internal
algorithm for scanning and assigning header cells p289 , with the principal cell, the
header list, the initial coordinate (principalx,y), and the increments Δx=−1 and Δy=0.
4.
For each value of x from principalx to principalx+principalwidth-1, run the internal
algorithm for scanning and assigning header cells p289 , with the principal cell, the
header list, the initial coordinate (x,principaly), and the increments Δx=0 and Δy=−1.
5.
If the principal cell is anchored in a row group p285 , then add all header cells that are
row group headers p290 and are anchored in the same row group with an x-coordinate
less than or equal to principalx+principalwidth-1 and a y-coordinate less than or equal
to principaly+principalheight-1 to header list.
6.
If the principal cell is anchored in a column group p285 , then add all header cells that
are column group headers p290 and are anchored in the same column group with an xcoordinate less than or equal to principalx+principalwidth-1 and a y-coordinate less
than or equal to principaly+principalheight-1 to header list.
4.
Remove all the empty cells p290 from the header list.
5.
Remove any duplicates from the header list.
6.
Remove principal cell from the header list if it is there.
7.
Assign the headers in the header list to the principal cell.
The internal algorithm for scanning and assigning header cells, given a principal cell, a header list, an
initial coordinate (initialx, initialy), and Δx and Δy increments, is as follows:
1.
Let x equal initialx.
2.
Let y equal initialy.
3.
Let opaque headers be an empty list of cells.
4.↪ If principal cell is a header cell
Let in header block be true, and let headers from current header block be a list of cells
containing just the principal cell.
↪ Otherwise
Let in header block be false and let headers from current header block be an empty list of
cells.
5.
Loop: Increment x by Δx; increment y by Δy.
Note: For each invocation of this algorithm, one of Δx and Δy will be −1, and the
other will be 0.
6.
If either x or y is less than 0, then abort this internal algorithm.
289
7.
If there is no cell covering slot (x, y), or if there is more than one cell covering slot (x, y), return to the
substep labeled loop.
8.
Let current cell be the cell covering slot (x, y).
9.↪ If current cell is a header cell
1.
Set in header block to true.
2.
Add current cell to headers from current header block.
3.
Let blocked be false.
4.↪ If Δx is 0
If there are any cells in the opaque headers list anchored with the same xcoordinate as the current cell, and with the same width as current cell, then
let blocked be true.
If the current cell is not a column header p290 , then let blocked be true.
↪ If Δy is 0
If there are any cells in the opaque headers list anchored with the same ycoordinate as the current cell, and with the same height as current cell,
then let blocked be true.
If the current cell is not a row header p290 , then let blocked be true.
5.
If blocked is false, then add the current cell to the headers list.
↪ If current cell is a data cell and in header block is true
Set in header block to false. Add all the cells in headers from current header block to the
opaque headers list, and empty the headers from current header block list.
10.
Return to the step labeled loop.
A header cell anchored at the slot with coordinate (x, y) with width width and height height is said to be a column
header if any of the following conditions are true:
•
The cell's scope p283 attribute is in the column p283 state, or
•
The cell's scope p283 attribute is in the auto p283 state, and there are no data cells in any of the cells
covering slots with y-coordinates y .. y+height-1.
A header cell anchored at the slot with coordinate (x, y) with width width and height height is said to be a row
header if any of the following conditions are true:
•
The cell's scope p283 attribute is in the row p283 state, or
•
The cell's scope p283 attribute is in the auto p283 state, the cell is not a column header p290 , and there are no
data cells in any of the cells covering slots with x-coordinates x .. x+width-1.
A header cell is said to be a column group header if its scope p283 attribute is in the column group p283 state.
A header cell is said to be a row group header if its scope p283 attribute is in the row group p283 state.
A cell is said to be an empty cell if it contains no elements and its text content, if any, consists only of
White_Space p34 characters.
4.9.13 Examples
This section is non-normative.
The following shows how might one mark up the bottom part of table 45 of the Smithsonian physical tables,
Volume 71:
Specification values: Steel , Castings ,
Ann. A.S.T.M. A27-16, Class B;* P max. 0.06; S max. 0.05.
Grade.
Yield Point.
Ultimate tensile strength
Per cent elong. 50.8mm or 2 in.
Per cent reduct. area.
290
kg/mm2
lb/in2
Hard
0.45 ultimate
56.2
80,000
15
20
Medium
0.45 ultimate
49.2
70,000
18
25
Soft
0.45 ultimate
42.2
60,000
22
30
This table could look like this:
Specification values: Steel, Castings, Ann. A.S.T.M. A27-16, Class B;* P max. 0.06; S max. 0.05.
Grade.
Hard . . . . .
Medium . . . .
Soft . . . . . .
Yield Point.
0.45 ultimate
0.45 ultimate
0.45 ultimate
Ultimate tensile strength
kg/mm
56.2
49.2
42.2
2
lb/in
2
80,000
70,000
60,000
Per cent
elong.
50.8 mm
or 2 in.
Per cent
reduct.
area.
15
18
22
20
25
30
The following shows how one might mark up the gross margin table on page 46 of Apple, Inc's 10-K filing for fiscal
year 2008:
2008
2007
2006
Net sales
$ 32,479
$ 24,006
$ 19,315
Cost of sales
21,334
15,852
13,717
Gross margin
$ 11,145
$ 8,154
291
$ 5,598
Gross margin percentage
34.3%
34.0%
29.0%
This table could look like this:
2008
2007
2006
Net sales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cost of sales . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gross margin . . . . . . . . . . . . . . . . . . . . . . . . . . . .
$ 32,479
21,334
$ 11,145
$ 24,006
15,852
$ 8,154
$ 19,315
13,717
$ 5,598
Gross margin percentage . . . . . . . . . . . . . . . . . . .
34.3%
34.0%
29.0%
The following shows how one might mark up the operating expenses table from lower on the same page of that
document:
2008 2007 2006
Research and development
$ 1,109 $ 782 $ 712
Percentage of net sales
3.4% 3.3% 3.7%
Selling, general, and administrative
$ 3,761 $ 2,963 $ 2,433
Percentage of net sales
11.6% 12.3% 12.6%
This table could look like this:
Research and development . . . . . . . . . . . . . . . . . . . . .
Percentage of net sales . . . . . . . . . . . . . . . . . . . . . .
Selling, general, and administrative . . . . . . . . . . . . . .
Percentage of net sales . . . . . . . . . . . . . . . . . . . . . .
2008
2007
2006
$ 1,109
3.4%
$ 3,761
11.6%
$ 782
3.3%
$ 2,963
12.3%
$ 712
3.7%
$ 2,433
12.6%
4.10 Forms
4.10.1 Introduction
This section is non-normative.
Forms allow unscripted client-server interaction: given a form, a user can provide data, submit it to the server, and
have the server act on it accordingly (e.g. returning the results of a search or calculation). The elements used in
forms can also be used for user interaction with no associated submission mechanism, in conjunction with scripts.
Writing a form consists of several steps, which can be performed in any order: writing the user interface,
implementing the server-side processing, and configuring the user interface to communicate with the server.
4.10.1.1 Writing a form's user interface
This section is non-normative.
For the purposes of this brief introduction, we will create a pizza ordering form.
Any form starts with a form p297 element, inside which are placed the controls. Most controls are represented by the
input p303 element, which by default provides a one-line text field. To label a control, the label p301 element is used;
the label text and the control itself go inside the label p301 element. Each part of a form is considered a
paragraph p93 , and is typically separated from other parts using p p148 elements. Putting this together, here is how
one might ask for the customer's name:
292
To let the user select the size of the pizza, we can use a set of radio buttons. Radio buttons also use the input p303
element, this time with a type p304 attribute with the value radio p319 . To make the radio buttons work as a group,
they are given a common name using the name p354 attribute. To group a batch of controls together, such as, in this
case, the radio buttons, one can use the fieldset p300 element. The title of such a group of controls is given by the
first element in the fieldset p300 , which has to be a legend p301 element.
Note: Changes from the previous step are highlighted.
To pick toppings, we can use checkboxes. These use the input p303 element with a type p304 attribute with the value
checkbox p318 :
The pizzeria for which this form is being written is always making mistakes, so it needs a way to contact the
customer. For this purpose, we can use form controls specifically for telephone numbers (input p303 elements with
their type p304 attribute set to tel p308 ) and e-mail addresses (input p303 elements with their type p304 attribute set to
email p309 ):
We can use an input p303 element with its type p304 attribute set to time p314 to ask for a delivery time. Many of these
form controls have attributes to control exactly what values can be specified; in this case, three attributes of
particular interest are min p328 , max p328 , and step p329 . These set the minimum time, the maximum time, and the
interval between allowed values (in seconds). This pizzeria only delivers between 11am and 9pm, and doesn't
promise anything better than 15 minute increments, which we can mark up as follows:
The textarea p341 element can be used to provide a free-form text field. In this instance, we are going to use it to
provide a space for the customer to give delivery instructions:
Finally, to make the form submittable we use the button p332 element:
4.10.1.2 Implementing the server-side processing for a form
This section is non-normative.
294
The exact details for writing a server-side processor are out of scope for this specification. For the purposes of this
introduction, we will assume that the script at https://pizza.example.com/order.cgi is configured to accept
submissions using the application/x-www-form-urlencoded p356 format, expecting the following parameters sent
in an HTTP POST body:
custname
Customer's name
custtel
Customer's telephone number
custemail
Customer's e-mail address
size
The pizza size, either small, medium, or large
toppings
The topping, specified once for each selected topping, with the allowed values being bacon, cheese, onion,
and mushroom
delivery
The requested delivery time
comments
The delivery instructions
4.10.1.3 Configuring a form to communicate with a server
This section is non-normative.
Form submissions are exposed to servers in a variety of ways, most commonly as HTTP GET or POST requests. To
specify the exact method used, the method p355 attribute is specified on the form p297 element. This doesn't specify
how the form data is encoded, though; to specify that, you use the enctype p356 attribute. You also have to specify
the URL p51 of the service that will handle the submitted data, using the action p355 attribute.
For each form control you want submitted, you then have to give a name that will be used to refer to the data in
the submission. We already specified the name for the group of radio buttons; the same attribute (name p354 ) also
specifies the submission name. Radio buttons can be distinguished from each other in the submission by giving
them different values, using the value p306 attribute.
Multiple controls can have the same name; for example, here we give all the checkboxes the same name, and the
server distinguishes which checkbox was checked by seeing which values are submitted with that name — like the
radio buttons, they are also given unique values with the value p306 attribute.
Given the settings in the previous section, this all becomes:
295
For example, if the customer entered "Denise Lawrence" as their name, "555-321-8642" as their telephone
number, did not specify an e-mail address, asked for a medium-sized pizza, selected the Extra Cheese and
Mushroom toppings, entered a delivery time of 7pm, and left the delivery instructions text field blank, the user
agent would submit the following to the online Web service:
custname=Denise+Lawrence&custtel=555-321-8624&custemail=&size=medium&topping=cheese&topping=mushroom&
4.10.1.4 Client-side form validation
This section is non-normative.
Forms can be annotated in such a way that the user agent will check the user's input before the form is submitted.
The server still has to verify the input is valid (since hostile users can easily bypass the form validation), but it
allows the user to avoid the wait incurred by having the server be the sole checker of the user's input.
The simplest annotation is the required p326 attribute, which can be specified on input p303 elements to indicate
that the form is not to be submitted until a value is given. By adding this attribute to the customer name and
delivery time fields, we allow the user agent to notify the user when the user submits the form without filling in
those fields:
It is also possible to limit the length of the input, using the maxlength p355 attribute. By adding this to the
textarea p341 element, we can limit users to 1000 characters, preventing them from writing huge essays to the
busy delivery drivers instead of staying focused and to the point:
4.10.2 Categories
Mostly for historical reasons, elements in this section fall into several overlapping (but subtly different) categories
in addition to the usual ones like flow content p91 , phrasing content p91 , and interactive content p92 .
A number of the elements are form-associated elements, which means they can have a form owner p353 and, to
expose this, have a form p353 content attribute with a matching form p354 IDL attribute.
⇒ button p332 , fieldset p300 , input p303 , keygen p344 , label p301 , meter p349 , object p208 , output p346 ,
progress p348 , select p334 , textarea p341
The form-associated elements p297 fall into several subcategories:
Listed elements
Denotes elements that are listed in the form.elements p299 and fieldset.elements p301 APIs.
⇒ button p332 , fieldset p300 , input p303 , keygen p344 , object p208 , output p346 , select p334 , textarea p341
Labelable elements
Denotes elements that can be associated with label p301 elements.
⇒ button p332 , input p303 , keygen p344 , meter p349 , output p346 , progress p348 , select p334 , textarea p341
Submittable elements
Denotes elements that can be used for constructing the form data set p361 when a form p297 element is
submitted p361 .
⇒ button p332 , input p303 , keygen p344 , object p208 , select p334 , textarea p341
Resettable elements
Denotes elements that can be affected when a form p297 element is reset p366 .
⇒ input p303 , keygen p344 , output p346 , select p334 , textarea p341
In addition, some submittable elements p297 can be, depending on their attributes, buttons. The prose below
defines when an element is a button. Some buttons are specifically submit buttons.
Note: The object p208 element is also a form-associated element p297 and can, with the use of a
suitable plugin p27 , partake in form submission p360 .
4.10.3 The form element
Categories
Flow content p91 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Flow content p91 , but with no form p297 element descendants.
Content attributes:
Global attributes p82
accept-charset p298
action p355
autocomplete p298
enctype p356
method p355
name p298
novalidate p356
target p356
DOM interface:
[OverrideBuiltins]
interface HTMLFormElement : HTMLElement {
attribute DOMString acceptCharset;
attribute DOMString action;
297
attribute
attribute
attribute
attribute
attribute
attribute
boolean autocomplete;
DOMString enctype;
DOMString method;
DOMString name;
boolean noValidate;
DOMString target;
readonly attribute HTMLFormControlsCollection elements;
readonly attribute long length;
caller getter any item(in unsigned long index);
caller getter any namedItem(in DOMString name);
void submit();
void reset();
boolean checkValidity();
void dispatchFormInput();
void dispatchFormChange();
};
The form p297 element represents p638 a collection of form-associated elements p297 , some of which can represent
editable values that can be submitted to a server for processing.
The accept-charset attribute gives the character encodings that are to be used for the submission. If specified,
the value must be an ordered set of unique space-separated tokens p49 , and each token must be an ASCII caseinsensitive p33 match for the preferred MIME name p28 of an ASCII-compatible character encoding p28 .
[IANACHARSET] p701
The name attribute represents the form p297 's name within the forms p77 collection. The value must not be the empty
string, and the value must be unique amongst the form p297 elements in the forms p77 collection that it is in, if any.
The autocomplete attribute is an enumerated attribute p34 . The attribute has two states. The on keyword maps to
the on state, and the off keyword maps to the off state. The attribute may also be omitted. The missing value
default is the on p298 state. The off p298 state indicates that by default, input p303 elements in the form will have their
resulting autocompletion state p324 set to off; the on p298 state indicates that by default, input p303 elements in the
form will have their resulting autocompletion state p324 set to on.
The action p355 , enctype p356 , method p355 , novalidate p356 , and target p356 attributes are attributes for form
submission p355 .
This box is non-normative. Implementation requirements are given below this box.
form . elements p299
Returns an HTMLCollection p59 of the form controls in the form (excluding image buttons for historical
reasons).
form . length p299
Returns the number of form controls in the form (excluding image buttons for historical reasons).
element = form . item p299 (index)
form[index]
form(index)
Returns the indexth element in the form (excluding image buttons for historical reasons).
element = form . namedItem p299 (name)
form[name]
form(name)
Returns the form control in the form with the given ID or name p354 (excluding image buttons for
historical reasons).
Once an element has been referenced using a particular name, that name will continue being
available as a way to reference that element in this method, even if the element's actual ID or name p354
changes, for as long as the element remains in the Document p31 .
If there are multiple matching items, then a NodeList p31 object containing all those elements is
returned.
298
Returns null if no element with that ID p84 or name p354 could be found.
form . submit p299 ()
Submits the form.
form . reset p299 ()
Resets the form.
form . checkValidity p300 ()
Returns true if the form's controls are all valid; otherwise, returns false.
form . dispatchFormInput p300 ()
Dispatches a forminput event at all the form controls.
form . dispatchFormChange p300 ()
Dispatches a formchange event at all the form controls.
The autocomplete and name IDL attributes must reflect p57 the respective content attributes of the same name.
The acceptCharset IDL attribute must reflect p57 the accept-charset p298 content attribute.
The elements IDL attribute must return an HTMLFormControlsCollection p61 rooted at the Document p31 node,
whose filter matches listed elements p297 whose form owner p353 is the form p297 element, with the exception of
input p303 elements whose type p304 attribute is in the Image Button p321 state, which must, for historical reasons, be
excluded from this particular collection.
The length IDL attribute must return the number of nodes represented p59 by the elements p299 collection.
The indices of the supported indexed properties at any instant are the indices supported by the object returned by
the elements p299 attribute at that instant.
The item(index) method must return the value returned by the method of the same name on the elements p299
collection, when invoked with the same argument.
Each form p297 element has a mapping of names to elements called the past names map. It is used to persist
names of controls even when they change names.
The names of the supported named properties are the union of the names currently supported by the object
returned by the elements p299 attribute, and the names currently in the past names map p299 .
The namedItem(name) method, when called, must run the following steps:
1.
2.
If name is one of the names of the supported named properties of the object returned by the
elements p299 attribute, then run these substeps:
1.
Let candidate be the object returned by the namedItem() p62 method on the object returned by
the elements p299 attribute when passed the name argument.
2.
If candidate is an element, then add a mapping from name to candidate in the form p297
element's past names map p299 , replacing the previous entry with the same name, if any.
3.
Return candidate and abort these steps.
Otherwise, name is the name of one of the entries in the form p297 element's past names map p299 : return
the object associated with name in that map.
If an element listed in the form p297 element's past names map p299 is removed from the Document p31 , then its
entries must be removed from the map.
The submit() method, when invoked, must submit p361 the form p297 element from the form p297 element itself, with
the scripted-submit flag set.
The reset() method, when invoked, must run the following steps:
1.
If the form p297 element is marked as locked for reset p299 , then abort these steps.
2.
Mark the form p297 element as locked for reset.
3.
Reset p366 the form p297 element.
299
4.
Unmark the form p297 element as locked for reset p299 .
If the checkValidity() method is invoked, the user agent must statically validate the constraints p357 of the
form p297 element, and return true if the constraint validation return a positive result, and false if it returned a
negative result.
If the dispatchFormInput() method is invoked, the user agent must broadcast forminput events p366 from the
form p297 element.
If the dispatchFormChange() method is invoked, the user agent must broadcast formchange events p366 from the
form p297 element.
This example shows two search forms:
4.10.4 The fieldset element
Categories
Flow content p91 .
Sectioning root p144 .
Listed p297 form-associated element p297 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Optionally a legend p301 element, followed by flow content p91 .
Content attributes:
Global attributes p82
disabled p300
form p353
name p354
DOM interface:
interface HTMLFieldSetElement : HTMLElement {
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute DOMString name;
readonly attribute DOMString type;
readonly attribute HTMLFormControlsCollection elements;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
};
The fieldset p300 element represents p638 a set of form controls optionally grouped under a common name.
The name of the group is given by the first legend p301 element that is a child of the fieldset p300 element, if any.
The remainder of the descendants form the group.
The disabled attribute, when specified, causes all the form control descendants of the fieldset p300 element,
excluding those that are descendants of the fieldset p300 element's first legend p301 element child, if any, to be
disabled p354 .
The form p353 attribute is used to explicitly associate the fieldset p300 element with its form owner p353 . The name p354
attribute represents the element's name.
300
This box is non-normative. Implementation requirements are given below this box.
fieldset . type
p301
Returns the string "fieldset".
fieldset . elements p299
Returns an HTMLCollection p59 of the form controls in the element.
The disabled IDL attribute must reflect p57 the content attribute of the same name.
The type IDL attribute must return the string "fieldset".
The elements IDL attribute must return an HTMLFormControlsCollection p61 rooted at the fieldset p300 element,
whose filter matches listed elements p297 .
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 .
Constraint validation: fieldset p300 elements are always barred from constraint validation p356 .
The following snippet shows a fieldset with a checkbox in the legend that controls whether or not the
fieldset is enabled. The contents of the fieldset consist of two required text fields and an optional year/
month control.
Name on card:
Card number:
Expiry date:
4.10.5 The legend element
Categories
None.
Contexts in which this element may be used:
As the first child of a fieldset p300 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
interface HTMLLegendElement : HTMLElement {
readonly attribute HTMLFormElement form;
};
The legend p301 element represents p638 a caption for the rest of the contents of the legend p301 element's parent
fieldset p300 element, if any.
This box is non-normative. Implementation requirements are given below this box.
legend . form
p301
Returns the element's form p297 element, if any, or null otherwise.
The form IDL attribute's behavior depends on whether the legend p301 element is in a fieldset p300 element or not.
If the legend p301 has a fieldset p300 element as its parent, then the form p301 IDL attribute must return the same
value as the form p354 IDL attribute on that fieldset p300 element. Otherwise, it must return null.
4.10.6 The label element
301
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but with no descendant labelable form-associated elements p297 unless it is the
element's labeled control p302 , and no descendant label p301 elements.
Content attributes:
Global attributes p82
form p353
for p302
DOM interface:
interface HTMLLabelElement : HTMLElement {
readonly attribute HTMLFormElement form;
attribute DOMString htmlFor;
readonly attribute HTMLElement control;
};
The label p301 represents p638 a caption in a user interface. The caption can be associated with a specific form
control, known as the label p301 element's labeled control, either using for p302 attribute, or by putting the form
control inside the label p301 element itself.
Except where otherwise specified by the following rules, a label p301 element has no labeled control p302 .
The for attribute may be specified to indicate a form control with which the caption is to be associated. If the
attribute is specified, the attribute's value must be the ID of a labelable form-associated element p297 in the same
Document p31 as the label p301 element. If the attribute is specified and there is an element in the Document p31
whose ID is equal to the value of the for p302 attribute, and the first such element is a labelable form-associated
element p297 , then that element is the label p301 element's labeled control p302 .
If the for p302 attribute is not specified, but the label p301 element has a labelable form-associated element p297
descendant, then the first such descendant in tree order p27 is the label p301 element's labeled control p302 .
The label p301 element's exact default presentation and behavior, in particular what its activation behavior p93
might be, if anything, should match the platform's label behavior.
For example, on platforms where clicking a checkbox label checks the checkbox, clicking the label p301 in
the following snippet could trigger the user agent to run synthetic click activation steps p92 on the input p303
element, as if the element itself had been triggered by the user:
Full name: Format: First Last
Age:
Post code: Format: AB12 3CD
4.10.7 The input element
Categories
Flow content p91 .
Phrasing content p91 .
If the type p304 attribute is not in the Hidden p307 state: Interactive content p92 .
Listed p297 , labelable p297 , submittable p297 , and resettable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Empty.
Content attributes:
Global attributes p82
accept p320
alt p322
autocomplete p324
autofocus p354
checked p306
disabled p354
form p353
formaction p355
formenctype p356
formmethod p355
formnovalidate p356
formtarget p356
height p271
list p324
max p328
maxlength p327
min p328
multiple p327
name p354
pattern p328
placeholder p329
readonly p325
required p326
size p326
src p321
step p329
type p304
value p306
width p271
DOM interface:
interface HTMLInputElement : HTMLElement {
attribute DOMString accept;
attribute DOMString alt;
attribute boolean autocomplete;
attribute boolean autofocus;
attribute boolean defaultChecked;
attribute boolean checked;
attribute boolean disabled;
readonly attribute HTMLFormElement form;
readonly attribute FileList files;
303
attribute
attribute
attribute
attribute
attribute
attribute
attribute
readonly attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
readonly attribute
attribute
DOMString formAction;
DOMString formEnctype;
DOMString formMethod;
boolean formNoValidate;
DOMString formTarget;
DOMString height;
boolean indeterminate;
HTMLElement list;
DOMString max;
long maxLength;
DOMString min;
boolean multiple;
DOMString name;
DOMString pattern;
DOMString placeholder;
boolean readOnly;
boolean required;
unsigned long size;
DOMString src;
DOMString step;
DOMString type;
DOMString defaultValue;
DOMString value;
Date valueAsDate;
double valueAsNumber;
HTMLOptionElement selectedOption;
DOMString width;
void stepUp(in optional long n);
void stepDown(in optional long n);
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
void select();
attribute unsigned long selectionStart;
attribute unsigned long selectionEnd;
void setSelectionRange(in unsigned long start, in unsigned long end);
};
The input p303 element represents p638 a typed data field, usually with a form control to allow the user to edit the
data.
The type attribute controls the data type (and associated control) of the element. It is an enumerated attribute p34 .
The following table lists the keywords and states for the attribute — the keywords in the left column map to the
states in the cell in the second column on the same row as the keyword.
Keyword
p307
Data type
Control type
hidden
Hidden
An arbitrary string
n/a
text
Text p307
Text with no line breaks
Text field
search
Search p307
Text with no line breaks
Search field
tel
Telephone p308
Text with no line breaks
A text field
url
URL p308
An absolute IRI
A text field
email
E-mail p309
An e-mail address or list of e-mail addresses
A text field
Text with no line breaks (sensitive information)
Text field that
obscures data entry
p310
password
Password
datetime
Date and
Time p310
A date and time (year, month, day, hour, minute, second, fraction of a second) with
the time zone set to UTC
A date and time
control
date
Date p311
A date (year, month, day) with no time zone
A date control
month
Month p312
A date consisting of a year and a month with no time zone
A month control
A date consisting of a week-year number and a week number with no time zone
A week control
week
304
State
Week
p313
Keyword
State
Time p314
time
datetime- Local Date
local
and Time p314
Data type
Control type
A time (hour, minute, seconds, fractional seconds) with no time zone
A time control
A date and time (year, month, day, hour, minute, second, fraction of a second) with no A date and time
time zone
control
number
Number p315
A numerical value
A text field or spinner
control
range
Range p316
A numerical value, with the extra semantic that the exact value is not important
A slider control or
similar
color
Color p318
An sRGB color with 8-bit red, green, and blue components
A color well
checkbox
Checkbox p318
A set of zero or more values from a predefined list
A checkbox
radio
Radio
Button p319
An enumerated value
A radio button
file
File
Upload p320
Zero or more files each with a MIME type p26 and optionally a file name
A label and a button
submit
Submit
Button p321
An enumerated value, with the extra semantic that it must be the last value selected
and initiates form submission
A button
image
Image
Button p321
A coordinate, relative to a particular image's size, with the extra semantic that it must Either a clickable
be the last value selected and initiates form submission
image, or a button
reset
Reset
Button p323
n/a
A button
button
Button p323
n/a
A button
The missing value default is the Text p307 state.
Which of the accept p320 , alt p322 , autocomplete p324 , checked p306 , formaction p355 , formenctype p356 , formmethod p355 ,
formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 , maxlength p327 , min p328 , multiple p327 ,
pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , src p321 , step p329 , and width p271 content
attributes, the checked p331 , files p331 , valueAsDate p331 , valueAsNumber p331 , list p332 , and selectedOption p332 IDL
attributes, the select() p517 method, the selectionStart p517 and selectionEnd p517 IDL attributes, the
setSelectionRange() p517 method, the stepUp() p331 and stepDown() p331 methods, and the input p332 and
change p332 events apply to an input p303 element depends on the state of its type p304 attribute. The following table
is non-normative and summarizes which of those content attributes, IDL attributes, methods, and events apply to
each state:
Hidden p307
EText p307 ,
Password p310 Date and Local Date Range p316 Color p318 Checkbox p318 ,
p309
and
Time p310 ,
Radio
Search p307 , mail
Time p314 ,
Date p311 ,
Button p319
URL p308 ,
p315
Month p312 , Number
Telephone p308
Week p313 ,
Time p314
Content attributes
accept p320
·
p322
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
autocomplete p324
·
Yes
Yes
Yes
Yes
Yes
Yes
Yes
·
checked p306
·
·
·
·
·
·
·
·
Yes
formaction p355
·
·
·
·
·
·
·
·
·
formenctype p356
·
·
·
·
·
·
·
·
·
formmethod p355
·
·
·
·
·
·
·
·
·
alt
p356
·
·
·
·
·
·
·
·
·
formtarget p356
·
·
·
·
·
·
·
·
·
height p271
·
·
·
·
·
·
·
·
·
list p324
·
Yes
Yes
·
Yes
Yes
Yes
Yes
·
max p328
·
·
·
·
Yes
Yes
Yes
·
·
maxlength p327
·
Yes
Yes
Yes
·
·
·
·
·
·
·
·
·
Yes
Yes
Yes
·
·
formnovalidate
min
p328
p327
·
·
Yes
·
·
·
·
·
·
pattern p328
·
Yes
Yes
Yes
·
·
·
·
·
placeholder p329
·
Yes
Yes
Yes
·
·
·
·
·
readonly p325
·
Yes
Yes
Yes
Yes
Yes
·
·
·
required p326
·
Yes
Yes
Yes
Yes
Yes
·
·
Yes
size p326
·
Yes
Yes
Yes
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
Yes
Yes
Yes
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
Yes
multiple
src
p321
step
p329
width p271
IDL attributes and methods
checked p331
305
Hidden p307
EText p307 ,
Password p310 Date and Local Date Range p316 Color p318 Checkbox p318 ,
p309
and
Time p310 ,
Radio
Search p307 , mail
Time p314 ,
Date p311 ,
Button p319
URL p308 ,
p315
Month p312 , Number
Telephone p308
Week p313 ,
Time p314
files p331
·
·
·
·
·
·
·
·
·
value p330
default p331
value p330
value p330
value p330
value p330
value p330
value p330
value p330
default/on p331
valueAsDate p331
·
·
·
·
Yes
·
·
·
·
valueAsNumber p331
·
·
·
·
Yes
Yes
Yes
·
·
list p332
·
Yes
Yes
·
Yes
Yes
Yes
Yes
·
selectedOption p332
·
Yes
Yes
·
Yes
Yes
Yes
Yes
·
·
Yes
Yes
Yes
·
·
·
·
·
select()
p517
p517
·
Yes
Yes
Yes
·
·
·
·
·
selectionEnd p517
·
Yes
Yes
Yes
·
·
·
·
·
setSelectionRange() p517
·
Yes
Yes
Yes
·
·
·
·
·
stepDown() p331
·
·
·
·
Yes
Yes
Yes
·
·
stepUp() p331
·
·
·
·
Yes
Yes
Yes
·
·
·
Yes
Yes
Yes
Yes
Yes
Yes
Yes
·
·
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
selectionStart
Events
input p332 event
change
p332
event
When an input p303 element's type p304 attribute changes state, and when the element is first created, the
element's rendering and behavior must change to the new state's accordingly and the value sanitization
algorithm, if one is defined for the type p304 attribute's new state, must be invoked.
Each input p303 element has a value p354 , which is exposed by the value p330 IDL attribute. Some states define an
algorithm to convert a string to a number, an algorithm to convert a number to a string, an algorithm
to convert a string to a Date object, and an algorithm to convert a Date object to a string, which are used
by max p328 , min p328 , step p329 , valueAsDate p331 , valueAsNumber p331 , stepDown() p331 , and stepUp() p331 .
Each input p303 element has a boolean dirty value flag. When it is true, the element is said to have a dirty
value. The dirty value flag p306 must be initially set to false when the element is created, and must be set to true
whenever the user interacts with the control in a way that changes the value p354 .
The value content attribute gives the default value p354 of the input p303 element. When the value p306 content
attribute is added, set, or removed, if the control does not have a dirty value p306 , the user agent must set the
value p354 of the element to the value of the value p306 content attribute, if there is one, or the empty string
otherwise, and then run the current value sanitization algorithm p306 , if one is defined.
Each input p303 element has a checkedness p354 , which is exposed by the checked p331 IDL attribute.
Each input p303 element has a boolean dirty checkedness flag. When it is true, the element is said to have a
dirty checkedness. The dirty checkedness flag p306 must be initially set to false when the element is created, and
must be set to true whenever the user interacts with the control in a way that changes the checkedness p354 .
The checked content attribute is a boolean attribute p34 that gives the default checkedness p354 of the input p303
element. When the checked p306 content attribute is added, if the control does not have dirty checkedness p306 , the
user agent must set the checkedness p354 of the element to true; when the checked p306 content attribute is
removed, if the control does not have dirty checkedness p306 , the user agent must set the checkedness p354 of the
element to false.
The reset algorithm p366 for input p303 elements is to set the dirty value flag p306 and dirty checkedness flag p306 back
to false, set the value p354 of the element to the value of the value p306 content attribute, if there is one, or the
empty string otherwise, set the checkedness p354 of the element to true if the element has a checked p306 content
attribute and false if it does not, and then invoke the value sanitization algorithm p306 , if the type p304 attribute's
current state defines one.
Each input p303 element is either mutable or immutable. Except where otherwise specified, an input p303 element
is always mutable p306 . Similarly, except where otherwise specified, the user agent should not allow the user to
modify the element's value p354 or checkedness p354 .
When an input p303 element is disabled p354 , it is immutable p306 .
When an input p303 element does not have a Document p31 node as one of its ancestors (i.e. when it is not in the
document), it is immutable p306 .
Note: The readonly p325 attribute can also in some cases (e.g. for the Date p311 state, but not the
Checkbox p318 state) make an input p303 element immutable p306 .
306
When an input p303 element is cloned, the element's value p354 , dirty value flag p306 , checkedness p354 , and dirty
checkedness flag p306 must be propagated to the clone when it is created.
The form p353 attribute is used to explicitly associate the input p303 element with its form owner p353 . The name p354
attribute represents the element's name. The disabled p354 attribute is used to make the control non-interactive
and to prevent its value from being submitted. The autofocus p354 attribute controls focus.
The indeterminate IDL attribute must initially be set to false. On getting, it must return the last value it was set
to. On setting, it must be set to the new value. It has no effect except for changing the appearance of
checkbox p318 controls.
The accept, alt, autocomplete, max, min, multiple, pattern, placeholder, required, size, src, step, and type
IDL attributes must reflect p57 the respective content attributes of the same name. The maxLength IDL attribute
must reflect p57 the maxlength p327 content attribute, limited to only non-negative numbers p58 . The readOnly IDL
attribute must reflect p57 the readonly p325 content attribute. The defaultChecked IDL attribute must reflect p57 the
checked p306 content attribute. The defaultValue IDL attribute must reflect p57 the value p306 content attribute.
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s. The select() p517 , selectionStart p517 , selectionEnd p517 , and
setSelectionRange() p517 methods and attributes expose the element's text selection.
4.10.7.1 States of the type p304 attribute
4.10.7.1.1 Hidden state
When an input p303 element's type p304 attribute is in the Hidden p307 state, the rules in this section apply.
The input p303 element represents p638 a value that is not intended to be examined or manipulated by the user.
Constraint validation: If an input p303 element's type p304 attribute is in the Hidden p307 state, it is barred from
constraint validation p356 .
If the name p306 attribute is present and has a value that is a case-sensitive p33 match for the string "_charset_",
then the element's value p306 attribute must be omitted.
Bookkeeping details
▪The value p330 IDL attribute applies to this element and is in mode default p331 .
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , autocomplete p324 ,
checked p306 , formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 ,
maxlength p327 , min p328 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , src p321 , step p329 , and
width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
selectionStart p517 , selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 ,
setSelectionRange() p517 , stepDown() p331 , and stepUp() p331 methods.
▪The input p332 and change p332 events do not apply.
4.10.7.1.2 Text state and Search state
When an input p303 element's type p304 attribute is in the Text p307 state or the Search p307 state, the rules in this
section apply.
The input p303 element represents p638 a one line plain text edit control for the element's value p354 .
Note: The difference between the Text p307 state and the Search p307 state is primarily stylistic:
on platforms where search fields are distinguished from regular text fields, the Search p307
state might result in an appearance consistent with the platform's search fields rather than
appearing like a regular text field.
If the element is mutable p306 , its value p354 should be editable by the user. User agents must not allow users to
insert U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters into the element's value p354 .
The value p306 attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D
CARRIAGE RETURN (CR) characters.
The value sanitization algorithm p306 is as follows: Strip line breaks p34 from the value p354 .
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , maxlength p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , and size p326 content attributes; list p332 ,
307
selectedOption p332 , selectionStart p517 , selectionEnd p517 , and value p330 IDL attributes; select() p517 and setSelectionRange() p517
methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , max p328 , min p328 , multiple p327 ,
src p321 , step p329 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , valueAsDate p331 , and valueAsNumber p331
IDL attributes; stepDown() p331 and stepUp() p331 methods.
4.10.7.1.3 Telephone state
When an input p303 element's type p304 attribute is in the Telephone p308 state, the rules in this section apply.
The input p303 element represents p638 a control for editing a telephone number given in the element's value p354 .
If the element is mutable p306 , its value p354 should be editable by the user. User agents may change the
punctuation of values p354 that the user enters. User agents must not allow users to insert U+000A LINE FEED (LF)
or U+000D CARRIAGE RETURN (CR) characters into the element's value p354 .
The value p306 attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D
CARRIAGE RETURN (CR) characters.
The value sanitization algorithm p306 is as follows: Strip line breaks p34 from the value p354 .
Note: Unlike the URL p308 and E-mail p309 types, the Telephone p308 type does not enforce a
particular syntax. This is intentional; in practice, telephone number fields tend to be free-form
fields, because there are a wide variety of valid phone numbers. Systems that need to enforce
a particular format are encouraged to use the setCustomValidity() p358 method to hook into the
client-side validation mechanism.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , maxlength p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , and size p326 content attributes; list p332 ,
selectedOption p332 , selectionStart p517 , selectionEnd p517 , and value p330 IDL attributes; select() p517 and setSelectionRange() p517
methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , max p328 , min p328 , multiple p327 ,
src p321 , step p329 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , valueAsDate p331 , and valueAsNumber p331
IDL attributes; stepDown() p331 and stepUp() p331 methods.
4.10.7.1.4 URL state
When an input p303 element's type p304 attribute is in the URL p308 state, the rules in this section apply.
The input p303 element represents p638 a control for editing a single absolute URL p52 given in the element's value p354 .
If the element is mutable p306 , the user agent should allow the user to change the URL represented by its value p354 .
User agents may allow the user to set the value p354 to a string that is not a valid p51 absolute URL p52 , but may also
or instead automatically escape characters entered by the user so that the value p354 is always a valid p51 absolute
URL p52 (even if that isn't the actual value seen and edited by the user in the interface). User agents should allow
the user to set the value p354 to the empty string. User agents must not allow users to insert U+000A LINE FEED
(LF) or U+000D CARRIAGE RETURN (CR) characters into the value p354 .
The value p306 attribute, if specified, must have a value that is a valid p51 absolute URL p52 .
The value sanitization algorithm p306 is as follows: Strip line breaks p34 from the value p354 .
Constraint validation: While the value p354 of the element is not a valid p51 absolute URL p52 , the element is
suffering from a type mismatch p357 .
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , maxlength p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , and size p326 content attributes; list p332 ,
selectedOption p332 , selectionStart p517 , selectionEnd p517 , and value p330 IDL attributes; select() p517 and setSelectionRange() p517
methods.
▪The value p330 IDL attribute is in mode value p330 .
308
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , max p328 , min p328 , multiple p327 ,
src p321 , step p329 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , valueAsDate p331 , and valueAsNumber p331
IDL attributes; stepDown() p331 and stepUp() p331 methods.
If a document contained the following markup:
...and the user had typed "www.w3", and the user agent had also found that the user had visited
http://www.w3.org/Consortium/#membership and http://www.w3.org/TR/XForms/ in the recent past,
then the rendering might look like this:
The first four URIs in this sample consist of the four URIs in the author-specified list that match the text the
user has entered, sorted lexically. Note how the UA is using the knowledge that the values are URIs to allow
the user to omit the scheme part and perform intelligent matching on the domain name.
The last two URIs (and probably many more, given the scrollbar's indications of more values being available)
are the matches from the user agent's session history data. This data is not made available to the page
DOM. In this particular case, the UA has no titles to provide for those values.
4.10.7.1.5 E-mail state
When an input p303 element's type p304 attribute is in the E-mail p309 state, the rules in this section apply.
The input p303 element represents p638 a control for editing a list of e-mail addresses given in the element's
value p354 .
If the element is mutable p306 , the user agent should allow the user to change the e-mail addresses represented by
its value p354 . If the multiple p327 attribute is specified, then the user agent should allow the user to select or
provide multiple addresses; otherwise, the user agent should act in a manner consistent with expecting the user
to provide a single e-mail address. User agents may allow the user to set the value p354 to a string that is not a
valid e-mail address list p310 . User agents should allow the user to set the value p354 to the empty string. User agents
must not allow users to insert U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters into the
value p354 . User agents may transform the value p354 for display and editing (e.g. converting punycode in the
value p354 to IDN in the display and vice versa).
If the multiple p327 attribute is specified on the element, then the value p306 attribute, if specified, must have a
value that is a valid e-mail address list p310 ; otherwise, the value p306 attribute, if specified, must have a value that
is a single valid e-mail address p310 .
The value sanitization algorithm p306 is as follows: Strip line breaks p34 from the value p354 .
Constraint validation: If the multiple p327 attribute is specified on the element, then, while the value p354 of the
element is not a valid e-mail address list p310 , the element is suffering from a type mismatch p357 ; otherwise, while
309
the value p354 of the element is not a single valid e-mail address p310 , the element is suffering from a type
mismatch p357 .
A valid e-mail address list is a set of comma-separated tokens p50 , where each token is itself a valid e-mail
address p310 . To obtain the list of tokens from a valid e-mail address list p310 , the user agent must split the string on
commas p50 .
A valid e-mail address is a string that matches the ABNF production 1*( atext / "." ) "@" ldhstr 1*( "." ldh-str ) where atext is defined in RFC 5322 section 3.2.3, and ldh-str is defined in RFC 1034
section 3.5. [ABNF] p700 [RFC5322] p703 [RFC1034] p702
Note: This requirement is a willful violation p17 of RFC 5322, which defines a syntax for e-mail
addresses that is simultaneously too strict (before the "@" character), too vague (after the
"@" character), and too lax (allowing comments, white space characters, and quoted strings in
manners unfamiliar to most users) to be of practical use here.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , maxlength p327 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , and size p326 content attributes;
list p332 , selectedOption p332 , selectionStart p517 , selectionEnd p517 , and value p330 IDL attributes; select() p517 and
setSelectionRange() p517 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , max p328 , min p328 , src p321 , step p329 ,
and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , valueAsDate p331 , and valueAsNumber p331
IDL attributes; stepDown() p331 and stepUp() p331 methods.
4.10.7.1.6 Password state
When an input p303 element's type p304 attribute is in the Password p310 state, the rules in this section apply.
The input p303 element represents p638 a one line plain text edit control for the element's value p354 . The user agent
should obscure the value so that people other than the user cannot see it.
If the element is mutable p306 , its value p354 should be editable by the user. User agents must not allow users to
insert U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters into the value p354 .
The value p306 attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D
CARRIAGE RETURN (CR) characters.
The value sanitization algorithm p306 is as follows: Strip line breaks p34 from the value p354 .
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
maxlength p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , and size p326 content attributes; selectionStart p517 ,
selectionEnd p517 , and value p330 IDL attributes; select() p517 , and setSelectionRange() p517 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 , min p328 ,
multiple p327 , src p321 , step p329 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
valueAsDate p331 , and valueAsNumber p331 IDL attributes; stepDown() p331 and stepUp() p331 methods.
4.10.7.1.7 Date and Time state
When an input p303 element's type p304 attribute is in the Date and Time p310 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
specific global date and time p44 . User agents may display the date and time in whatever time zone is appropriate
for the user.
If the element is mutable p306 , the user agent should allow the user to change the global date and time p44
represented by its value p354 , as obtained by parsing a global date and time p44 from it. User agents must not allow
the user to set the value p354 to a string that is not a valid global date and time string p44 expressed in UTC, though
user agents may allow the user to set and view the time in another time zone and silently translate the time to
and from the UTC time zone in the value p354 . If the user agent provides a user interface for selecting a global date
310
and time p44 , then the value p354 must be set to a valid global date and time string p44 expressed in UTC representing
the user's selection. User agents should allow the user to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid global date and time string p44 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is a valid global date and
time string p44 , then adjust the time so that the value p354 represents the same point in time but expressed in the
UTC time zone, otherwise, set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid global date and time string p44 . The max p328
attribute, if specified, must have a value that is a valid global date and time string p44 .
The step p329 attribute is expressed in seconds. The step scale factor p329 is 1000 (which converts the seconds to
milliseconds, as used in the other algorithms). The default step p329 is 60 seconds.
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest global date and time p44 for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a global
date and time p44 from input results in an error, then return an error; otherwise, return the number of milliseconds
elapsed from midnight UTC on the morning of 1970-01-01 (the time represented by the value
"1970-01-01T00:00:00.0Z") to the parsed global date and time p44 , ignoring leap seconds.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
global date and time string p44 expressed in UTC that represents the global date and time p44 that is input
milliseconds after midnight UTC on the morning of 1970-01-01 (the time represented by the value
"1970-01-01T00:00:00.0Z").
The algorithm to convert a string to a Date object p306 , given a string input, is as follows: If parsing a
global date and time p44 from input results in an error, then return an error; otherwise, return a Date object
representing the parsed global date and time p44 , expressed in UTC.
The algorithm to convert a Date object to a string p306 , given a Date object input, is as follows: Return a
valid global date and time string p44 expressed in UTC that represents the global date and time p44 that is
represented by input.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsDate p331 ,
valueAsNumber p331 , and selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , and
selectionEnd p517 IDL attributes; select() p517 and setSelectionRange() p517 methods.
The following fragment shows part of a calendar application. A user can specify a date and time for a
meeting (in his local time zone, probably, though the user agent can allow the user to change that), and
since the submitted data includes the time-zone offset, the application can ensure that the meeting is
shown at the correct time regardless of the time zones used by all the participants.
Add Meeting
Meeting name:
Meeting time:
Had the application used the datetime-local p314 type instead, the calendar application would have also
had to explicitly determine which time zone the user intended.
4.10.7.1.8 Date state
When an input p303 element's type p304 attribute is in the Date p311 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
specific date p41 .
If the element is mutable p306 , the user agent should allow the user to change the date p41 represented by its
value p354 , as obtained by parsing a date p41 from it. User agents must not allow the user to set the value p354 to a
string that is not a valid date string p41 . If the user agent provides a user interface for selecting a date p41 , then the
311
value p354 must be set to a valid date string p41 representing the user's selection. User agents should allow the user
to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid date string p41 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid date string p41 ,
then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid date string p41 . The max p328 attribute, if specified,
must have a value that is a valid date string p41 .
The step p329 attribute is expressed in days. The step scale factor p329 is 86,400,000 (which converts the days to
milliseconds, as used in the other algorithms). The default step p329 is 1 day.
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest date p41 for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a date p41
from input results in an error, then return an error; otherwise, return the number of milliseconds elapsed from
midnight UTC on the morning of 1970-01-01 (the time represented by the value "1970-01-01T00:00:00.0Z") to
midnight UTC on the morning of the parsed date p41 , ignoring leap seconds.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
date string p41 that represents the date p41 that, in UTC, is current input milliseconds after midnight UTC on the
morning of 1970-01-01 (the time represented by the value "1970-01-01T00:00:00.0Z").
The algorithm to convert a string to a Date object p306 , given a string input, is as follows: If parsing a
date p41 from input results in an error, then return an error; otherwise, return a Date object representing midnight
UTC on the morning of the parsed date p41 .
The algorithm to convert a Date object to a string p306 , given a Date object input, is as follows: Return a
valid date string p41 that represents the date p41 current at the time represented by input in the UTC time zone.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsDate p331 ,
valueAsNumber p331 , and selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , selectionStart p517 , and selectionEnd p517 IDL
attributes; select() p517 and setSelectionRange() p517 methods.
4.10.7.1.9 Month state
When an input p303 element's type p304 attribute is in the Month p312 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
specific month p41 .
If the element is mutable p306 , the user agent should allow the user to change the month p41 represented by its
value p354 , as obtained by parsing a month p41 from it. User agents must not allow the user to set the value p354 to a
string that is not a valid month string p41 . If the user agent provides a user interface for selecting a month p41 , then
the value p354 must be set to a valid month string p41 representing the user's selection. User agents should allow the
user to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid month string p41 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid month
string p41 , then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid month string p41 . The max p328 attribute, if
specified, must have a value that is a valid month string p41 .
The step p329 attribute is expressed in months. The step scale factor p329 is 1 (there is no conversion needed as the
algorithms use months). The default step p329 is 1 month.
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest month p41 for which the element would not suffer from a step mismatch p357 .
312
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a
month p41 from input results in an error, then return an error; otherwise, return the number of months between
January 1970 and the parsed month p41 .
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
month string p41 that represents the month p41 that has input months between it and January 1970.
The algorithm to convert a string to a Date object p306 , given a string input, is as follows: If parsing a
month p41 from input results in an error, then return an error; otherwise, return a Date object representing midnight
UTC on the morning of the first day of the parsed month p41 .
The algorithm to convert a Date object to a string p306 , given a Date object input, is as follows: Return a
valid month string p41 that represents the month p41 current at the time represented by input in the UTC time zone.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsDate p331 ,
valueAsNumber p331 , and selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , and
selectionEnd p517 IDL attributes; select() p517 and setSelectionRange() p517 methods.
4.10.7.1.10 Week state
When an input p303 element's type p304 attribute is in the Week p313 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
specific week p45 .
If the element is mutable p306 , the user agent should allow the user to change the week p45 represented by its
value p354 , as obtained by parsing a week p46 from it. User agents must not allow the user to set the value p354 to a
string that is not a valid week string p46 . If the user agent provides a user interface for selecting a week p45 , then the
value p354 must be set to a valid week string p46 representing the user's selection. User agents should allow the user
to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid week string p46 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid week string p46 ,
then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid week string p46 . The max p328 attribute, if
specified, must have a value that is a valid week string p46 .
The step p329 attribute is expressed in weeks. The step scale factor p329 is 604,800,000 (which converts the weeks to
milliseconds, as used in the other algorithms). The default step p329 is 1 week. The default step base p329 is
−259,200,000 (the start of week 1970-W01).
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest week p45 for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a week
string p46 from input results in an error, then return an error; otherwise, return the number of milliseconds elapsed
from midnight UTC on the morning of 1970-01-01 (the time represented by the value "1970-01-01T00:00:00.0Z")
to midnight UTC on the morning of the Monday of the parsed week p45 , ignoring leap seconds.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
week string p46 that represents the week p45 that, in UTC, is current input milliseconds after midnight UTC on the
morning of 1970-01-01 (the time represented by the value "1970-01-01T00:00:00.0Z").
The algorithm to convert a string to a Date object p306 , given a string input, is as follows: If parsing a
week p46 from input results in an error, then return an error; otherwise, return a Date object representing midnight
UTC on the morning of the Monday of the parsed week p45 .
The algorithm to convert a Date object to a string p306 , given a Date object input, is as follows: Return a
valid week string p46 that represents the week p45 current at the time represented by input in the UTC time zone.
Bookkeeping details
313
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsDate p331 ,
valueAsNumber p331 , and selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , and
selectionEnd p517 IDL attributes; select() p517 and setSelectionRange() p517 methods.
4.10.7.1.11 Time state
When an input p303 element's type p304 attribute is in the Time p314 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
specific time p42 .
If the element is mutable p306 , the user agent should allow the user to change the time p42 represented by its
value p354 , as obtained by parsing a time p42 from it. User agents must not allow the user to set the value p354 to a
string that is not a valid time string p42 . If the user agent provides a user interface for selecting a time p42 , then the
value p354 must be set to a valid time string p42 representing the user's selection. User agents should allow the user
to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid time string p42 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid time string p42 ,
then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid time string p42 . The max p328 attribute, if specified,
must have a value that is a valid time string p42 .
The step p329 attribute is expressed in seconds. The step scale factor p329 is 1000 (which converts the seconds to
milliseconds, as used in the other algorithms). The default step p329 is 60 seconds.
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest time p42 for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a time p42
from input results in an error, then return an error; otherwise, return the number of milliseconds elapsed from
midnight to the parsed time p42 on a day with no time changes.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
time string p42 that represents the time p42 that is input milliseconds after midnight on a day with no time changes.
The algorithm to convert a string to a Date object p306 , given a string input, is as follows: If parsing a
time p42 from input results in an error, then return an error; otherwise, return a Date object representing the parsed
time p42 in UTC on 1970-01-01.
The algorithm to convert a Date object to a string p306 , given a Date object input, is as follows: Return a
valid time string p42 that represents the UTC time p42 component that is represented by input.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsDate p331 ,
valueAsNumber p331 , and selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , and
selectionEnd p517 IDL attributes; select() p517 and setSelectionRange() p517 methods.
4.10.7.1.12 Local Date and Time state
When an input p303 element's type p304 attribute is in the Local Date and Time p314 state, the rules in this section
apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a local
date and time p43 , with no time-zone offset information.
314
If the element is mutable p306 , the user agent should allow the user to change the date and time p43 represented by
its value p354 , as obtained by parsing a date and time p43 from it. User agents must not allow the user to set the
value p354 to a string that is not a valid local date and time string p43 . If the user agent provides a user interface for
selecting a local date and time p43 , then the value p354 must be set to a valid local date and time string p43
representing the user's selection. User agents should allow the user to set the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid local date and time string p43 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid local date and
time string p43 , then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid local date and time string p43 . The max p328
attribute, if specified, must have a value that is a valid local date and time string p43 .
The step p329 attribute is expressed in seconds. The step scale factor p329 is 1000 (which converts the seconds to
milliseconds, as used in the other algorithms). The default step p329 is 60 seconds.
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest local date and time p43 for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If parsing a date
and time p43 from input results in an error, then return an error; otherwise, return the number of milliseconds
elapsed from midnight on the morning of 1970-01-01 (the time represented by the value
"1970-01-01T00:00:00.0") to the parsed local date and time p43 , ignoring leap seconds.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
local date and time string p43 that represents the date and time that is input milliseconds after midnight on the
morning of 1970-01-01 (the time represented by the value "1970-01-01T00:00:00.0").
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsNumber p331 , and
selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , selectionEnd p517 ,
and valueAsDate p331 IDL attributes; select() p517 and setSelectionRange() p517 methods.
The following example shows part of a flight booking application. The application uses an input p303 element
with its type p304 attribute set to datetime-local p314 , and it then interprets the given date and time in the
time zone of the selected airport.
Destination
Airport:
Departure time:
If the application instead used the datetime p310 type, then the user would have to work out the time-zone
conversions himself, which is clearly not a good user experience!
4.10.7.1.13 Number state
When an input p303 element's type p304 attribute is in the Number p315 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
number.
If the element is mutable p306 , the user agent should allow the user to change the number represented by its
value p354 , as obtained from applying the rules for parsing floating point number values p36 to it. User agents must
315
not allow the user to set the value p354 to a string that is not a valid floating point number p36 . If the user agent
provides a user interface for selecting a number, then the value p354 must be set to the best representation of the
number representing the user's selection as a floating point number p36 . User agents should allow the user to set
the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid floating point number p36 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid floating point
number p36 , then set it to the empty string instead.
The min p328 attribute, if specified, must have a value that is a valid floating point number p36 . The max p328 attribute,
if specified, must have a value that is a valid floating point number p36 .
The step scale factor p329 is 1. The default step p329 is 1 (allowing only integers, unless the min p328 attribute has a
non-integer value).
When the element is suffering from a step mismatch p357 , the user agent may round the element's value p354 to the
nearest number for which the element would not suffer from a step mismatch p357 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If applying the
rules for parsing floating point number values p36 to input results in an error, then return an error; otherwise, return
the resulting number.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
floating point number p36 that represents input.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , readonly p325 , required p326 , and step p329 content attributes; list p332 , value p330 , valueAsNumber p331 , and
selectedOption p332 IDL attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , selectionEnd p517 ,
and valueAsDate p331 IDL attributes; select() p517 and setSelectionRange() p517 methods.
4.10.7.1.14 Range state
When an input p303 element's type p304 attribute is in the Range p316 state, the rules in this section apply.
The input p303 element represents p638 a control for setting the element's value p354 to a string representing a
number, but with the caveat that the exact value is not important, letting UAs provide a simpler interface than
they do for the Number p315 state.
Note: In this state, the range and step constraints are enforced even during user input, and
there is no way to set the value to the empty string.
If the element is mutable p306 , the user agent should allow the user to change the number represented by its
value p354 , as obtained from applying the rules for parsing floating point number values p36 to it. User agents must
not allow the user to set the value p354 to a string that is not a valid floating point number p36 . If the user agent
provides a user interface for selecting a number, then the value p354 must be set to a best representation of the
number representing the user's selection as a floating point number p36 . User agents must not allow the user to set
the value p354 to the empty string.
The value p306 attribute, if specified, must have a value that is a valid floating point number p36 .
The value sanitization algorithm p306 is as follows: If the value p354 of the element is not a valid floating point
number p36 , then set it to a valid floating point number p36 that represents the default value p316 .
The min p328 attribute, if specified, must have a value that is a valid floating point number p36 . The default
minimum p328 is 0. The max p328 attribute, if specified, must have a value that is a valid floating point number p36 . The
default maximum p328 is 100.
The default value is the minimum p328 plus half the difference between the minimum p328 and the maximum p328 ,
unless the maximum p328 is less than the minimum p328 , in which case the default value p316 is the minimum p328 .
When the element is suffering from an underflow p357 , the user agent must set the element's value p354 to a valid
floating point number p36 that represents the minimum p328 .
316
When the element is suffering from an overflow p357 , if the maximum p328 is not less than the minimum p328 , the user
agent must set the element's value p354 to a valid floating point number p36 that represents the maximum p328 .
The step scale factor p329 is 1. The default step p329 is 1 (allowing only integers, unless the min p328 attribute has a
non-integer value).
When the element is suffering from a step mismatch p357 , the user agent must round the element's value p354 to the
nearest number for which the element would not suffer from a step mismatch p357 , and which is greater than or
equal to the minimum p328 , and, if the maximum p328 is not less than the minimum p328 , which is less than or equal to
the maximum p328 .
The algorithm to convert a string to a number p306 , given a string input, is as follows: If applying the
rules for parsing floating point number values p36 to input results in an error, then return an error; otherwise, return
the resulting number.
The algorithm to convert a number to a string p306 , given a number input, is as follows: Return a valid
floating point number p36 that represents input.
Bookkeeping details
▪The following common input p303 element content attributes, IDL attributes, and methods apply to the element: autocomplete p324 ,
list p324 , max p328 , min p328 , and step p329 content attributes; list p332 , value p330 , valueAsNumber p331 , and selectedOption p332 IDL
attributes; stepDown() p331 and stepUp() p331 methods.
▪The value p330 IDL attribute is in mode value p330 .
▪The input p332 and change p332 events apply.
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , maxlength p327 , multiple p327 ,
pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , src p321 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , selectionStart p517 , selectionEnd p517 ,
and valueAsDate p331 IDL attributes; select() p517 and setSelectionRange() p517 methods.
Here is an example of a range control using an autocomplete list with the list p324 attribute. This could be
useful if there are values along the full range of the control that are especially important, such as
preconfigured light levels or typical speed limits in a range control used as a speed control. The following
markup fragment:
...with the following style sheet applied:
input { height: 75px; width: 49px; background: #D5CCBB; color: black; }
...might render as:
Note how the UA determined the orientation of the control from the ratio of the style-sheet-specified height
and width properties. The colors were similiarly derived from the style sheet. The tick marks, however, were
derived from the markup. In particular, the step p329 attribute has not affected the placement of tick marks,
the UA deciding to only use the author-specified completion values and then adding longer tick marks at the
extremes.
Note also how the invalid value +50 was completely ignored.
For another example, consider the following markup fragment:
The name of the file you picked is: (none)
Bookkeeping details
▪The following common input p303 element content attributes apply to the element:
▪The following common input p303 element content attributes and IDL attributes apply to the element: accept p320 , multiple p327 , and
required p326 ; files p331 and value p330 IDL attributes.
▪The value p330 IDL attribute is in mode filename p331 .
▪The change p332 event applies.
▪The following content attributes must not be specified and do not apply to the element: alt p322 , autocomplete p324 , checked p306 ,
formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 , maxlength p327 ,
min p328 , pattern p328 , placeholder p329 , readonly p325 , size p326 , src p321 , step p329 , and width p271 .
▪The element's value p306 attribute must be omitted.
▪The following IDL attributes and methods do not apply to the element: checked p331 , list p332 , selectedOption p332 , selectionStart p517 ,
selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 , setSelectionRange() p517 , stepDown() p331 ,
and stepUp() p331 methods.
▪The input p332 event does not apply.
4.10.7.1.19 Submit Button state
When an input p303 element's type p304 attribute is in the Submit Button p321 state, the rules in this section apply.
The input p303 element represents p638 a button that, when activated, submits the form. If the element has a
value p306 attribute, the button's label must be the value of that attribute; otherwise, it must be an
implementation-defined string that means "Submit" or some such. The element is a button p297 , specifically a
submit button p297 .
If the element is mutable p306 , the user agent should allow the user to activate the element.
The element's activation behavior p93 , if the element has a form owner p353 , is to submit p361 the form owner p353 from
the input p303 element; otherwise, it is to do nothing.
The formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , and formtarget p356 attributes are
attributes for form submission p355 .
Note: The formnovalidate p356 attribute can be used to make submit buttons that do not trigger
the constraint validation.
Bookkeeping details
▪The following common input p303 element content attributes and IDL attributes apply to the element: formaction p355 , formenctype p356 ,
formmethod p355 , formnovalidate p356 , and formtarget p356 content attributes; value p330 IDL attribute.
▪The value p330 IDL attribute is in mode default p331 .
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , autocomplete p324 ,
checked p306 , height p271 , list p324 , max p328 , maxlength p327 , min p328 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 ,
required p326 , size p326 , src p321 , step p329 , and width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
selectionStart p517 , selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 ,
setSelectionRange() p517 , stepDown() p331 , and stepUp() p331 methods.
▪The input p332 and change p332 events do not apply.
4.10.7.1.20 Image Button state
When an input p303 element's type p304 attribute is in the Image Button p321 state, the rules in this section apply.
The input p303 element represents p638 either an image from which a user can select a coordinate and submit the
form, or alternatively a button from which the user can submit the form. The element is a button p297 , specifically a
submit button p297 .
The image is given by the src attribute. The src p321 attribute must be present, and must contain a valid nonempty URL p51 referencing a non-interactive, optionally animated, image resource that is neither paged nor
scripted.
When any of the following events occur, unless the user agent cannot support images, or its support for images
has been disabled, or the user agent only fetches elements on demand, or the src p321 attribute's value is the
empty string, the user agent must resolve p51 the value of the src p321 attribute, relative to the element, and if that
is successful, must fetch p55 the resulting absolute URL p52 :
321
•
The input p303 element's type p304 attribute is first set to the Image Button p321 state (possibly when the
element is first created), and the src p321 attribute is present.
•
The input p303 element's type p304 attribute is changed back to the Image Button p321 state, and the src p321
attribute is present, and its value has changed since the last time the type p304 attribute was in the
Image Button p321 state.
•
The input p303 element's type p304 attribute is in the Image Button p321 state, and the src p321 attribute is
set or changed.
Fetching the image must delay the load event p619 of the element's document until the task p489 that is queued p490
by the networking task source p491 once the resource has been fetched p55 (defined below) has been run.
If the image was successfully obtained, with no network errors, and the image's type is a supported image type,
and the image is a valid image of that type, then the image is said to be available. If this is true before the image
is completely downloaded, each task p489 that is queued p490 by the networking task source p491 while the image is
being fetched p55 must update the presentation of the image appropriately.
The user agents should apply the image sniffing rules p57 to determine the type of the image, with the image's
associated Content-Type headers p57 giving the official type. If these rules are not applied, then the type of the
image must be the type given by the image's associated Content-Type headers p57 .
User agents must not support non-image resources with the input p303 element. User agents must not run
executable code embedded in the image resource. User agents must only display the first page of a multipage
resource. User agents must not allow the resource to act in an interactive fashion, but should honor any animation
in the resource.
The task p489 that is queued p490 by the networking task source p491 once the resource has been fetched p55 , must, if
the download was successful and the image is available p322 , queue a task p490 to fire a simple event p496 named
load at the input p303 element; and otherwise, if the fetching process fails without a response from the remote
server, or completes but the image is not a valid or supported image, queue a task p490 to fire a simple event p496
named error on the input p303 element.
The alt attribute provides the textual label for the alternative button for users and user agents who cannot use
the image. The alt p322 attribute must also be present, and must contain a non-empty string.
The input p303 element supports dimension attributes p271 .
If the src p321 attribute is set, and the image is available p322 and the user agent is configured to display that image,
then: The element represents p638 a control for selecting a coordinate p322 from the image specified by the src p321
attribute; if the element is mutable p306 , the user agent should allow the user to select this coordinate p322 . The
activation behavior p93 in this case consists of taking the user's selected coordinate p322 , and then, if the element
has a form owner p353 , submitting p361 the input p303 element's form owner p353 from the input p303 element. If the
user activates the control without explicitly selecting a coordinate, then the coordinate (0,0) must be assumed.
Otherwise, the element represents p638 a submit button whose label is given by the value of the alt p322 attribute; if
the element is mutable p306 , the user agent should allow the user to activate the button. The activation behavior p93
in this case consists of setting the selected coordinate p322 to (0,0), and then, if the element has a form owner p353 ,
submitting p361 the input p303 element's form owner p353 from the input p303 element.
The selected coordinate must consist of an x-component and a y-component. The coordinates represent the
position relative to the edge of the image, with the coordinate space having the positive x direction to the right,
and the positive y direction downwards.
The x-component must be a valid integer p35 representing a number x in the range −(borderleft+paddingleft) ≤ x ≤
width+borderright+paddingright, where width is the rendered width of the image, borderleft is the width of the
border on the left of the image, paddingleft is the width of the padding on the left of the image, borderright is the
width of the border on the right of the image, and paddingright is the width of the padding on the right of the
image, with all dimensions given in CSS pixels.
The y-component must be a valid integer p35 representing a number y in the range −(bordertop+paddingtop) ≤ y ≤
height+borderbottom+paddingbottom, where height is the rendered height of the image, bordertop is the width of
the border above the image, paddingtop is the width of the padding above the image, borderbottom is the width of
the border below the image, and paddingbottom is the width of the padding below the image, with all dimensions
given in CSS pixels.
Where a border or padding is missing, its width is zero CSS pixels.
The formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , and formtarget p356 attributes are
attributes for form submission p355 .
322
Bookkeeping details
▪The following common input p303 element content attributes and IDL attributes apply to the element: alt p322 , formaction p355 ,
formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , src p321 , and width p271 content attributes; value p330
IDL attribute.
▪The value p330 IDL attribute is in mode default p331 .
▪The following content attributes must not be specified and do not apply to the element: accept p320 , autocomplete p324 , checked p306 ,
list p324 , max p328 , maxlength p327 , min p328 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , and
step p329 .
▪The element's value p306 attribute must be omitted.
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
selectionStart p517 , selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 ,
setSelectionRange() p517 , stepDown() p331 , and stepUp() p331 methods.
▪The input p332 and change p332 events do not apply.
Note: Many aspects of this state's behavior are similar to the behavior of the img p186 element.
Readers are encouraged to read that section, where many of the same requirements are
described in more detail.
4.10.7.1.21 Reset Button state
When an input p303 element's type p304 attribute is in the Reset Button p323 state, the rules in this section apply.
The input p303 element represents p638 a button that, when activated, resets the form. If the element has a value p306
attribute, the button's label must be the value of that attribute; otherwise, it must be an implementation-defined
string that means "Reset" or some such. The element is a button p297 .
If the element is mutable p306 , the user agent should allow the user to activate the element.
The element's activation behavior p93 , if the element has a form owner p353 , is to reset p366 the form owner p353 ;
otherwise, it is to do nothing.
Constraint validation: The element is barred from constraint validation p356 .
Bookkeeping details
▪The value p330 IDL attribute applies to this element and is in mode default p331 .
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , autocomplete p324 ,
checked p306 , formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 ,
maxlength p327 , min p328 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , src p321 , step p329 , and
width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
selectionStart p517 , selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 ,
setSelectionRange() p517 , stepDown() p331 , and stepUp() p331 methods.
▪The input p332 and change p332 events do not apply.
4.10.7.1.22 Button state
When an input p303 element's type p304 attribute is in the Button p323 state, the rules in this section apply.
The input p303 element represents p638 a button with no default behavior. If the element has a value p306 attribute,
the button's label must be the value of that attribute; otherwise, it must be the empty string. The element is a
button p297 .
If the element is mutable p306 , the user agent should allow the user to activate the element. The element's
activation behavior p93 is to do nothing.
Constraint validation: The element is barred from constraint validation p356 .
Bookkeeping details
▪The value p330 IDL attribute applies to this element and is in mode default p331 .
▪The following content attributes must not be specified and do not apply to the element: accept p320 , alt p322 , autocomplete p324 ,
checked p306 , formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , formtarget p356 , height p271 , list p324 , max p328 ,
maxlength p327 , min p328 , multiple p327 , pattern p328 , placeholder p329 , readonly p325 , required p326 , size p326 , src p321 , step p329 , and
width p271 .
▪The following IDL attributes and methods do not apply to the element: checked p331 , files p331 , list p332 , selectedOption p332 ,
selectionStart p517 , selectionEnd p517 , valueAsDate p331 , and valueAsNumber p331 IDL attributes; select() p517 ,
setSelectionRange() p517 , stepDown() p331 , and stepUp() p331 methods.
▪The input p332 and change p332 events do not apply.
323
4.10.7.2 Common input p303 element attributes
These attributes only apply to an input p303 element if its type p304 attribute is in a state whose definition declares
that the attribute applies. When an attribute doesn't apply to an input p303 element, user agents must ignore p27 the
attribute, regardless of the requirements and definitions below.
4.10.7.2.1 The autocomplete p324 attribute
User agents sometimes have features for helping users fill forms in, for example prefilling the user's address
based on earlier user input.
The autocomplete attribute is an enumerated attribute p34 . The attribute has three states. The on keyword maps to
the on state, and the off keyword maps to the off state. The attribute may also be omitted. The missing value
default is the default state.
The off p324 state indicates either that the control's input data is particularly sensitive (for example the activation
code for a nuclear weapon); or that it is a value that will never be reused (for example a one-time-key for a bank
login) and the user will therefore have to explicitly enter the data each time, instead of being able to rely on the
UA to prefill the value for him; or that the document provides its own autocomplete mechanism and does not want
the user agent to provide autocompletion values.
Conversely, the on p324 state indicates that the value is not particularly sensitive and the user can expect to be able
to rely on his user agent to remember values he has entered for that control.
The default p324 state indicates that the user agent is to use the autocomplete p298 attribute on the element's form
owner p353 instead. (By default, the autocomplete p298 attribute of form p297 elements is in the on p298 state.)
Each input p303 element has a resulting autocompletion state, which is either on or off.
When an input p303 element is in one of the following conditions, the input p303 element's resulting autocompletion
state p324 is on; otherwise, the input p303 element's resulting autocompletion state p324 is off:
•
•
•
Its autocomplete p324 attribute is in the on p324 state.
Its autocomplete p324 attribute is in the default p324 state, and the element has no form owner p353 .
Its autocomplete p324 attribute is in the default p324 state, and the element's form owner p353 's
autocomplete p298 attribute is in the on p298 state.
When an input p303 element's resulting autocompletion state p324 is on, the user agent may store the value entered
by the user so that if the user returns to the page, the UA can prefill the form. Otherwise, the user agent should
not remember the control's value p354 , and should not offer past values to the user.
In addition, if the resulting autocompletion state p324 is off, values are reset p466 when traversing the history p465 .
The autocompletion mechanism must be implemented by the user agent acting as if the user had modified the
element's value p354 , and must be done at a time where the element is mutable p306 (e.g. just after the element has
been inserted into the document, or when the user agent stops parsing p618 ).
Banks frequently do not want UAs to prefill login information:
Account:
PIN:
A user agent may allow the user to override the resulting autocompletion state p324 and set it to always on, always
allowing values to be remembered and prefilled), or always off, never remembering values. However, the ability to
override the resulting autocompletion state p324 to on should not be trivially accessible, as there are significant
security implications for the user if all values are always remembered, regardless of the site's preferences.
4.10.7.2.2 The list p324 attribute
The list attribute is used to identify an element that lists predefined options suggested to the user.
If present, its value must be the ID of a datalist p338 element in the same document.
The suggestions source element is the first element in the document in tree order p27 to have an ID equal to the
value of the list p324 attribute, if that element is a datalist p338 element. If there is no list p324 attribute, or if
there is no element with that ID, or if the first element with that ID is not a datalist p338 element, then there is no
suggestions source element p324 .
If there is a suggestions source element p324 , then, when the user agent is allowing the user to edit the input p303
element's value p354 , the user agent should offer the suggestions represented by the suggestions source
element p324 to the user in a manner suitable for the type of control used. The user agent may use the suggestion's
label p340 to identify the suggestion if appropriate. If the user selects a suggestion, then the input p303 element's
value p354 must be set to the selected suggestion's value p340 , as if the user had written that value himself.
324
User agents must filter the suggestions to hide suggestions that the user would not be allowed to enter as the
input p303 element's value p354 , and should filter the suggestions to hide suggestions that would cause the element
to not satisfy its constraints p357 .
If the list p324 attribute does not apply, there is no suggestions source element p324 .
This URL field offers some suggestions.
Homepage:
Other URLs from the user's history might show also; this is up to the user agent.
This example demonstrates how to design a form that uses the autocompletion list feature while still
degrading usefully in legacy user agents.
If the autocompletion list is merely an aid, and is not important to the content, then simply using a
datalist p338 element with children option p339 elements is enough. To prevent the values from being
rendered in legacy user agents, they should be placed inside the value p340 attribute instead of inline.
Enter a breed:
However, if the values need to be shown in legacy UAs, then fallback content can be placed inside the
datalist p338 element, as follows:
Enter a breed:
or select one from the list:
(none selected)
Abyssinian
Alpaca
The fallback content will only be shown in UAs that don't support datalist p338 . The options, on the other
hand, will be detected by all UAs, even though they are not direct children of the datalist p338 element.
Note that if an option p339 element used in a datalist p338 is selected p340 , it will be selected by default by
legacy UAs (because it affects the select p334 ), but it will not have any effect on the input p303 element in
UAs that support datalist p338 .
4.10.7.2.3 The readonly p325 attribute
The readonly attribute is a boolean attribute p34 that controls whether or not the use can edit the form control.
When specified, the element is immutable p306 .
Constraint validation: If the readonly p325 attribute is specified on an input p303 element, the element is barred
from constraint validation p356 .
325
In the following example, the existing product identifiers cannot be modified, but they are still displayed as
part of the form, for consistency with the row representing a new product (where the identifier is not yet
filled in).
4.10.7.2.4 The size p326 attribute
The size attribute gives the number of characters that, in a visual rendering, the user agent is to allow the user to
see while editing the element's value p354 .
The size p326 attribute, if specified, must have a value that is a valid non-negative integer p35 greater than zero.
If the attribute is present, then its value must be parsed using the rules for parsing non-negative integers p35 , and if
the result is a number greater than zero, then the user agent should ensure that at least that many characters are
visible.
The size p307 IDL attribute is limited to only non-negative numbers greater than zero p58 .
4.10.7.2.5 The required p326 attribute
The required attribute is a boolean attribute p34 . When specified, the element is required.
Constraint validation: If the element is required p326 , and its value p330 IDL attribute applies and is in the mode
value p330 , and the element is mutable p306 , and the element's value p354 is the empty string, then the element is
suffering from being missing p357 .
The following form has two required fields, one for an e-mail address and one for a password. It also has a
third field that is only considerd valid if the user types the same password in the password field and this
third field.
Create new account
326
4.10.7.2.6 The multiple p327 attribute
The multiple attribute is a boolean attribute p34 that indicates whether the user is to be allowed to specify more
than one value.
The following extract shows how an e-mail client's "Cc" field could accept multiple e-mail addresses.
Cc:
If the user had, amongst many friends in his user contacts database, two friends "Arthur Dent" (with
address "art@example.net") and "Adam Josh" (with address "adamjosh@example.net"), then, after the user
has typed "a", the user agent might suggest these two e-mail addresses to the user.
The page could also link in the user's contacts database from the site:
Cc:
...
Suppose the user had entered "bob@example.net" into this text field, and then started typing a second email address starting with "a". The user agent might show both the two friends mentioned earlier, as well as
the "astrophy" and "astronomy" values given in the datalist p338 element.
The following extract shows how an e-mail client's "Attachments" field could accept multiple files for upload.
Attachments:
4.10.7.2.7 The maxlength p327 attribute
The maxlength attribute, when it applies, is a form control maxlength attribute p355 controlled by the input p303
element's dirty value flag p306 .
If the input p303 element has a maximum allowed value length p355 , then the code-point length p34 of the value of the
element's value p306 attribute must be equal to or less than the element's maximum allowed value length p355 .
The following extract shows how a messaging client's text entry could be arbitrarily restricted to a fixed
number of characters, thus forcing any conversion through this medium to be terse and discouraging
intelligent discourse.
What are you doing? Part number:
...could cause the UA to display an alert such as:
A part number is a digit followed by three uppercase letters.
You cannot complete this form until the field is correct.
When a control has a pattern p328 attribute, the title p84 attribute, if used, must describe the pattern. Additional
information could also be included, so long as it assists the user in filling in the control. Otherwise, assistive
technology would be impaired.
For instance, if the title attribute contained the caption of the control, assistive technology could end up
saying something like The text you have entered does not match the required pattern. Birthday,
which is not useful.
UAs may still show the title p107 in non-error situations (for example, as a tooltip when hovering over the control),
so authors should be careful not to word title p107 s as if an error has necessarily occurred.
4.10.7.2.9 The min p328 and max p328 attributes
The min and max attributes indicate the allowed range of values for the element.
Their syntax is defined by the section that defines the type p304 attribute's current state.
If the element has a min p328 attribute, and the result of applying the algorithm to convert a string to a number p306
to the value of the min p328 attribute is a number, then that number is the element's minimum; otherwise, if the
type p304 attribute's current state defines a default minimum, then that is the minimum p328 ; otherwise, the
element has no minimum p328 .
Constraint validation: When the element has a minimum p328 , and the result of applying the algorithm to convert
a string to a number p306 to the string given by the element's value p354 is a number, and the number obtained from
that algorithm is less than the minimum p328 , the element is suffering from an underflow p357 .
The min p328 attribute also defines the step base p329 .
If the element has a max p328 attribute, and the result of applying the algorithm to convert a string to a number p306
to the value of the max p328 attribute is a number, then that number is the element's maximum; otherwise, if the
type p304 attribute's current state defines a default maximum, then that is the maximum p328 ; otherwise, the
element has no maximum p328 .
Constraint validation: When the element has a maximum p328 , and the result of applying the algorithm to
convert a string to a number p306 to the string given by the element's value p354 is a number, and the number
obtained from that algorithm is more than the maximum p328 , the element is suffering from an overflow p357 .
The max p328 attribute's value (the maximum p328 ) must not be less than the min p328 attribute's value (its
minimum p328 ).
328
Note: If an element has a maximum p328 that is less than its minimum p328 , then so long as the
element has a value p354 , it will either be suffering from an underflow p357 or suffering from an
overflow p357 .
The following date control limits input to dates that are before the 1980s:
Mail Account
Name:
Address:
Password:
Description:
4.10.7.3 Common input p303 element APIs
This box is non-normative. Implementation requirements are given below this box.
input . value p330 [ = value ]
Returns the current value p354 of the form control.
Can be set, to change the value.
Throws an INVALID_STATE_ERR p70 exception if it is set to any value other than the empty string when
the control is a file upload control.
input . checked p331 [ = value ]
Returns the current checkedness p354 of the form control.
Can be set, to change the checkedness p354 .
input . files p331
Returns a FileList object listing the selected files p320 of the form control.
Throws an INVALID_STATE_ERR p70 exception if the control isn't a file control.
input . valueAsDate p331 [ = value ]
Returns a Date object representing the form control's value p354 , if applicable; otherwise, returns null.
Can be set, to change the value.
Throws an INVALID_STATE_ERR p70 exception if the control isn't date- or time-based.
input . valueAsNumber p331 [ = value ]
Returns a number representing the form control's value p354 , if applicable; otherwise, returns null.
Can be set, to change the value.
Throws an INVALID_STATE_ERR p70 exception if the control is neither date- or time-based nor numeric.
input . stepUp p331 ( [ n ] )
input . stepDown p331 ( [ n ] )
Changes the form control's value p354 by the value given in the step p329 attribute, multiplied by n. The
default is 1.
Throws INVALID_STATE_ERR p70 exception if the control is neither date- or time-based nor numeric, if
the step p329 attribute's value is "any", if the current value p354 could not be parsed, or if stepping in the
given direction by the given amount would take the value out of range.
input . list p332
Returns the datalist p338 element indicated by the list p324 attribute.
input . selectedOption p332
Returns the option p339 element from the datalist p338 element indicated by the list p324 attribute that
matches the form control's value p354 .
The value IDL attribute allows scripts to manipulate the value p354 of an input p303 element. The attribute is in one
of the following modes, which define its behavior:
value
On getting, it must return the current value p354 of the element. On setting, it must set the element's value p354
to the new value, set the element's dirty value flag p306 to true, and then invoke the value sanitization
algorithm p306 , if the element's type p304 attribute's current state defines one.
330
default
On getting, if the element has a value p306 attribute, it must return that attribute's value; otherwise, it must
return the empty string. On setting, it must set the element's value p306 attribute to the new value.
default/on
On getting, if the element has a value p306 attribute, it must return that attribute's value; otherwise, it must
return the string "on". On setting, it must set the element's value p306 attribute to the new value.
filename
On getting, it must return the string "C:\fakepath\" followed by the filename of the first file in the list of
selected files p320 , if any, or the empty string if the list is empty. On setting, if the new value is the empty
string, it must empty the list of selected files p320 ; otherwise, it must throw an INVALID_STATE_ERR p70
exception.
The checked IDL attribute allows scripts to manipulate the checkedness p354 of an input p303 element. On getting, it
must return the current checkedness p354 of the element; and on setting, it must set the element's checkedness p354
to the new value and set the element's dirty checkedness flag p306 to true.
The files IDL attribute allows scripts to access the element's selected files p320 . On getting, if the IDL attribute
applies, it must return a FileList object that represents the current selected files p320 . The same object must be
returned until the list of selected files p320 changes. If the IDL attribute does not apply, then it must instead throw
an INVALID_STATE_ERR p70 exception. [FILEAPI] p701
The valueAsDate IDL attribute represents the value p354 of the element, interpreted as a date.
On getting, if the valueAsDate p331 attribute does not apply, as defined for the input p303 element's type p304
attribute's current state, then return null. Otherwise, run the algorithm to convert a string to a Date object p306
defined for that state; if the algorithm returned a Date object, then return it, otherwise, return null.
On setting, if the valueAsDate p331 attribute does not apply, as defined for the input p303 element's type p304
attribute's current state, then throw an INVALID_STATE_ERR p70 exception; otherwise, if the new value is null, then
set the value p354 of the element to the empty string; otherwise, run the algorithm to convert a Date object to a
string p306 , as defined for that state, on the new value, and set the value p354 of the element to resulting string.
The valueAsNumber IDL attribute represents the value p354 of the element, interpreted as a number.
On getting, if the valueAsNumber p331 attribute does not apply, as defined for the input p303 element's type p304
attribute's current state, then return a Not-a-Number (NaN) value. Otherwise, if the valueAsDate p331 attribute
applies, run the algorithm to convert a string to a Date object p306 defined for that state; if the algorithm returned a
Date object, then return the time value of the object (the number of milliseconds from midnight UTC the morning
of 1970-01-01 to the time represented by the Date object), otherwise, return a Not-a-Number (NaN) value.
Otherwise, run the algorithm to convert a string to a number p306 defined for that state; if the algorithm returned a
number, then return it, otherwise, return a Not-a-Number (NaN) value.
On setting, if the valueAsNumber p331 attribute does not apply, as defined for the input p303 element's type p304
attribute's current state, then throw an INVALID_STATE_ERR p70 exception. Otherwise, if the valueAsDate p331
attribute applies, run the algorithm to convert a Date object to a string p306 defined for that state, passing it a Date
object whose time value is the new value, and set the value p354 of the element to resulting string. Otherwise, run
the algorithm to convert a number to a string p306 , as defined for that state, on the new value, and set the value p354
of the element to resulting string.
The stepDown(n) and stepUp(n) methods, when invoked, must run the following algorithm:
1.
If the stepDown() p331 and stepUp() p331 methods do not apply, as defined for the input p303 element's
type p304 attribute's current state, then throw an INVALID_STATE_ERR p70 exception, and abort these
steps.
2.
If the element has no allowed value step p329 , then throw an INVALID_STATE_ERR p70 exception, and abort
these steps.
3.
If applying the algorithm to convert a string to a number p306 to the string given by the element's
value p354 results in an error, then throw an INVALID_STATE_ERR p70 exception, and abort these steps;
otherwise, let value be the result of that algorithm.
4.
Let n be the argument, or 1 if the argument was omitted.
5.
Let delta be the allowed value step p329 multiplied by n.
6.
If the method invoked was the stepDown() p331 method, negate delta.
331
7.
Let value be the result of adding delta to value.
8.
If the element has a minimum p328 , and the value is less than that minimum p328 , then throw a
INVALID_STATE_ERR p70 exception.
9.
If the element has a maximum p328 , and the value is greater than that maximum p328 , then throw a
INVALID_STATE_ERR p70 exception.
10.
Let value as string be the result of running the algorithm to convert a number to a string p306 , as defined
for the input p303 element's type p304 attribute's current state, on value.
11.
Set the value p354 of the element to value as string.
The list IDL attribute must return the current suggestions source element p324 , if any, or null otherwise.
The selectedOption IDL attribute must return the first option p339 element, in tree order p27 , to be a child of the
suggestions source element p324 and whose value p340 matches the input p303 element's value p354 , if any. If there is
no suggestions source element p324 , or if it contains no matching option p339 element, then the selectedOption p332
attribute must return null.
4.10.7.4 Common event behaviors
When the input event applies, any time the user causes the element's value p354 to change, the user agent must
queue a task p490 to fire a simple event p496 that bubbles named input at the input p303 element, then broadcast
forminput events p366 at the input p303 element's form owner p353 . User agents may wait for a suitable break in the
user's interaction before queuing the task; for example, a user agent could wait for the user to have not hit a key
for 100ms, so as to only fire the event when the user pauses, instead of continuously for each keystroke.
Examples of a user changing the element's value p354 would include the user typing into a text field, pasting
a new value into the field, or undoing an edit in that field. Some user interactions do not cause changes to
the value, e.g. hitting the "delete" key in an empty text field, or replacing some text in the field with text
from the clipboard that happens to be exactly the same text.
When the change event applies, if the element does not have an activation behavior p93 defined but uses a user
interface that involves an explicit commit action, then any time the user commits a change to the element's
value p354 or list of selected files p320 , the user agent must queue a task p490 to fire a simple event p496 that bubbles
named change at the input p303 element, then broadcast formchange events p366 at the input p303 element's form
owner p353 .
An example of a user interface with a commit action would be a File Upload p320 control that consists of a
single button that brings up a file selection dialog: when the dialog is closed, if that the file selection p320
changed as a result, then the user has committed a new file selection p320 .
Another example of a user interface with a commit action would be a Date p311 control that allows both textbased user input and user selection from a drop-down calendar: while text input might not have an explicit
commit step, selecting a date from the drop down calendar and then dismissing the drop down would be a
commit action.
When the user agent changes the element's value p354 on behalf of the user (e.g. as part of a form prefilling
feature), the user agent must follow these steps:
1.
If the input p332 event applies, queue a task p490 to fire a simple event p496 that bubbles named input at
the input p303 element.
2.
If the input p332 event applies, broadcast forminput events p366 at the input p303 element's form
owner p353 .
3.
If the change p332 event applies, queue a task p490 to fire a simple event p496 that bubbles named change at
the input p303 element.
4.
If the change p332 event applies, broadcast formchange events p366 at the input p303 element's form
owner p353 .
Note: In addition, when the change p332 event applies, change events can also be fired as part of
the element's activation behavior p93 and as part of the unfocusing steps p511 .
The task source p490 for these tasks p489 is the user interaction task source p491 .
4.10.8 The button element
332
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Listed p297 , labelable p297 , and submittable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but there must be no interactive content p92 descendant.
Content attributes:
Global attributes p82
autofocus p354
disabled p354
form p353
formaction p355
formenctype p356
formmethod p355
formnovalidate p356
formtarget p356
name p354
type p333
value p334
DOM interface:
interface HTMLButtonElement : HTMLElement {
attribute boolean autofocus;
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute DOMString formAction;
attribute DOMString formEnctype;
attribute DOMString formMethod;
attribute DOMString formNoValidate;
attribute DOMString formTarget;
attribute DOMString name;
attribute DOMString type;
attribute DOMString value;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
};
The button p332 element represents p638 a button. If the element is not disabled p354 , then the user agent should
allow the user to activate the button.
The element is a button p297 .
The type attribute controls the behavior of the button when it is activated. It is an enumerated attribute p34 . The
following table lists the keywords and states for the attribute — the keywords in the left column map to the states
in the cell in the second column on the same row as the keyword.
Keyword
State
Brief description
submit
Submit Button p334 Submits the form.
reset
Reset Button p334
button
Button
p334
Resets the form.
Does nothing.
The missing value default is the Submit Button p334 state.
If the type p333 attribute is in the Submit Button p334 state, the element is specifically a submit button p297 .
333
Constraint validation: If the type p333 attribute is in the Reset Button p334 state or the Button p334 state, the
element is barred from constraint validation p356 .
If the element is not disabled p354 , the activation behavior p93 of the button p332 element is to run the steps defined
in the following list for the current state of the element's type p333 attribute.
Submit Button
If the element has a form owner p353 , the element must submit p361 the form owner p353 from the button p332
element.
Reset Button
If the element has a form owner p353 , the element must reset p366 the form owner p353 .
Button
Do nothing.
The form p353 attribute is used to explicitly associate the button p332 element with its form owner p353 . The name p354
attribute represents the element's name. The disabled p354 attribute is used to make the control non-interactive
and to prevent its value from being submitted. The autofocus p354 attribute controls focus. The formaction p355 ,
formenctype p356 , formmethod p355 , formnovalidate p356 , and formtarget p356 attributes are attributes for form
submission p355 .
Note: The formnovalidate p356 attribute can be used to make submit buttons that do not trigger
the constraint validation.
The formaction p355 , formenctype p356 , formmethod p355 , formnovalidate p356 , and formtarget p356 must not be
specified if the element's type p333 attribute is not in the Submit Button p334 state.
The value attribute gives the element's value for the purposes of form submission. The element's value p354 is the
value of the element's value p334 attribute, if there is one, or the empty string otherwise.
Note: A button (and its value) is only included in the form submission if the button itself was
used to initiate the form submission.
The value and type IDL attributes must reflect p57 the respective content attributes of the same name.
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s.
The following button is labeled "Show hint" and pops up a dialog box when activated:
Show hint
4.10.9 The select element
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Listed p297 , labelable p297 , submittable p297 , and resettable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Zero or more option p339 or optgroup p338 elements.
Content attributes:
Global attributes p82
autofocus p354
disabled p354
form p353
multiple p335
name p354
size p335
334
DOM interface:
interface HTMLSelectElement : HTMLElement {
attribute boolean autofocus;
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute boolean multiple;
attribute DOMString name;
attribute unsigned long size;
readonly attribute DOMString type;
readonly attribute HTMLOptionsCollection options;
attribute unsigned long length;
caller getter any item(in unsigned long index);
caller getter any namedItem(in DOMString name);
void add(in HTMLElement element, in optional HTMLElement before);
void add(in HTMLElement element, in long before);
void remove(in long index);
readonly attribute HTMLCollection selectedOptions;
attribute long selectedIndex;
attribute DOMString value;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
};
The select p334 element represents a control for selecting amongst a set of options.
The multiple attribute is a boolean attribute p34 . If the attribute is present, then the select p334 element
represents p638 a control for selecting zero or more options from the list of options p335 . If the attribute is absent,
then the select p334 element represents p638 a control for selecting a single option from the list of options p335 .
The list of options for a select p334 element consists of all the option p339 element children of the select p334
element, and all the option p339 element children of all the optgroup p338 element children of the select p334
element, in tree order p27 .
The size attribute gives the number of options to show to the user. The size p326 attribute, if specified, must have
a value that is a valid non-negative integer p35 greater than zero. If the multiple p335 attribute is present, then the
size p326 attribute's default value is 4. If the multiple p335 attribute is absent, then the size p326 attribute's default
value is 1.
If the multiple p335 attribute is absent, and the element is not disabled p354 , then the user agent should allow the
user to pick an option p339 element in its list of options p335 that is itself not disabled p340 . Upon this option p339
element being picked (either through a click, or through unfocusing the element after changing its value, or
through a menu command p379 , or through any other mechanism), and before the relevant user interaction event is
queued (e.g. before the click p31 event), the user agent must set the selectedness p340 of the picked option p339
element to true and then queue a task p490 to fire a simple event p496 that bubbles named change at the select p334
element, using the user interaction task source p491 as the task source, then broadcast formchange events p366 at
the element's form owner p353 .
If the multiple p335 attribute is absent, whenever an option p339 element in the select p334 element's list of
options p335 has its selectedness p340 set to true, and whenever an option p339 element with its selectedness p340 set
to true is added to the select p334 element's list of options p335 , the user agent must set the selectedness p340 of all
the other option p339 element in its list of options p335 to false.
If the multiple p335 attribute is absent, whenever there are no option p339 elements in the select p334 element's list
of options p335 that have their selectedness p340 set to true, the user agent must set the selectedness p340 of the first
option p339 element in the list of options p335 in tree order p27 that is not disabled p340 , if any, to true.
If the multiple p335 attribute is present, and the element is not disabled p354 , then the user agent should allow the
user to toggle the selectedness p340 of the option p339 elements in its list of options p335 that are themselves not
335
disabled p340 (either through a click, or through a menu command p379 , or any other mechanism). Upon the
selectedness p340 of one or more option p339 elements being changed by the user, and before the relevant user
interaction event is queued (e.g. before a related click p31 event), the user agent must queue a task p490 to fire a
simple event p496 that bubbles named change at the select p334 element, using the user interaction task source p491
as the task source, then broadcast formchange events p366 at the element's form owner p353 .
The reset algorithm p366 for select p334 elements is to go through all the option p339 elements in the element's list of
options p335 , and set their selectedness p340 to true if the option p339 element has a selected p340 attribute, and false
otherwise.
The form p353 attribute is used to explicitly associate the select p334 element with its form owner p353 . The name p354
attribute represents the element's name. The disabled p354 attribute is used to make the control non-interactive
and to prevent its value from being submitted. The autofocus p354 attribute controls focus.
This box is non-normative. Implementation requirements are given below this box.
select . type
p337
Returns "select-multiple" if the element has a multiple p335 attribute, and "select-one" otherwise.
select . options p337
Returns an HTMLOptionsCollection p62 of the list of options p335 .
select . length p337 [ = value ]
Returns the number of elements in the list of options p335 .
When set to a smaller number, truncates the number of option p339 elements in the select p334 .
When set to a greater number, adds new blank option p339 elements to the select p334 .
element = select . item p337 (index)
select[index]
select(index)
Returns the item with index index from the list of options p335 . The items are sorted in tree order p27 .
Returns null if index is out of range.
element = select . namedItem p337 (name)
select[name]
select(name)
Returns the item with ID or name p662 name from the list of options p335 .
If there are multiple matching items, then a NodeList p31 object containing all those elements is
returned.
Returns null if no element with that ID could be found.
select . add p337 (element [, before ])
Inserts element before the node given by before.
The before argument can be a number, in which case element is inserted before the item with that
number, or an element from the list of options p335 , in which case element is inserted before that
element.
If before is omitted, null, or a number out of range, then element will be added at the end of the list.
This method will throw a HIERARCHY_REQUEST_ERR p70 exception if element is an ancestor of the
element into which it is to be inserted. If element is not an option p339 or optgroup p338 element, then
the method does nothing.
select . selectedOptions p337
Returns an HTMLCollection p59 of the list of options p335 that are selected.
select . selectedIndex p337 [ = value ]
Returns the index of the first selected item, if any, or −1 if there is no selected item.
Can be set, to change the selection.
select . value p337 [ = value ]
Returns the value p354 of the first selected item, if any, or the empty string if there is no selected item.
Can be set, to change the selection.
336
The type IDL attribute, on getting, must return the string "select-one" if the multiple p335 attribute is absent, and
the string "select-multiple" if the multiple p335 attribute is present.
The options IDL attribute must return an HTMLOptionsCollection p62 rooted at the select p334 node, whose filter
matches the elements in the list of options p335 .
The options p337 collection is also mirrored on the HTMLSelectElement p335 object. The indices of the supported
indexed properties at any instant are the indices supported by the object returned by the options p337 attribute at
that instant. The names of the supported named properties at any instant are the names supported by the object
returned by the options p337 attribute at that instant.
The length IDL attribute must return the number of nodes represented p59 by the options p337 collection. On
setting, it must act like the attribute of the same name on the options p337 collection.
The item(index) method must return the value returned by the method of the same name on the options p337
collection, when invoked with the same argument.
The namedItem(name) method must return the value returned by the method of the same name on the
options p337 collection, when invoked with the same argument.
Similarly, the add() and remove() methods must act like their namesake methods on that same options p337
collection.
The selectedOptions IDL attribute must return an HTMLCollection p59 rooted at the select p334 node, whose filter
matches the elements in the list of options p335 that have their selectedness p340 set to true.
The selectedIndex IDL attribute, on getting, must return the index p340 of the first option p339 element in the list of
options p335 in tree order p27 that has its selectedness p340 set to true, if any. If there isn't one, then it must return −1.
On setting, the selectedIndex p337 attribute must set the selectedness p340 of all the option p339 elements in the list
of options p335 to false, and then the option p339 element in the list of options p335 whose index p340 is the given new
value, if any, must have its selectedness p340 set to true.
The value IDL attribute, on getting, must return the value p340 of the first option p339 element in the list of
options p335 in tree order p27 that has its selectedness p340 set to true, if any. If there isn't one, then it must return the
empty string.
On setting, the value p337 attribute must set the selectedness p340 of all the option p339 elements in the list of
options p335 to false, and then first the option p339 element in the list of options p335 , in tree order p27 , whose value p340
is equal to the given new value, if any, must have its selectedness p340 set to true.
The multiple and size IDL attributes must reflect p57 the respective content attributes of the same name. The
size p337 IDL attribute limited to only non-negative numbers greater than zero p58 .
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s.
The following example shows how a select p334 element can be used to offer the user with a set of options
from which the user can select a single option. The default option is preselected.
Select unit type:
Miner
Puffer
Snipey
Max
Firebot
Here, the user is offered a set of options from which he can select any number. By default, all five options
are selected.
Select unit types to enable on this map:
Miner
Puffer
Snipey
Max
Firebot
337
4.10.10 The datalist element
Categories
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Either: phrasing content p91 .
Or: Zero or more option p339 elements.
Content attributes:
Global attributes p82
DOM interface:
interface HTMLDataListElement : HTMLElement {
readonly attribute HTMLCollection options;
};
The datalist p338 element represents a set of option p339 elements that represent predefined options for other
controls. The contents of the element represents fallback content for legacy user agents, intermixed with
option p339 elements that represent the predefined options. In the rendering, the datalist p338 element
represents p638 nothing and it, along with its children, should be hidden.
The datalist p338 element is hooked up to an input p303 element using the list p324 attribute on the input p303
element.
Each option p339 element that is a descendant of the datalist p338 element, that is not disabled p340 , and whose
value p340 is a string that isn't the empty string, represents a suggestion. Each suggestion has a value p340 and a
label p340 .
This box is non-normative. Implementation requirements are given below this box.
datalist . options p338
Returns an HTMLCollection p59 of the options elements of the table.
The options IDL attribute must return an HTMLCollection p59 rooted at the datalist p338 node, whose filter
matches option p339 elements.
Constraint validation: If an element has a datalist p338 element ancestor, it is barred from constraint
validation p356 .
4.10.11 The optgroup element
Categories
None.
Contexts in which this element may be used:
As a child of a select p334 element.
Content model:
Zero or more option p339 elements.
Content attributes:
Global attributes p82
disabled p339
label p339
DOM interface:
interface HTMLOptGroupElement : HTMLElement {
attribute boolean disabled;
338
attribute DOMString label;
};
The optgroup p338 element represents p638 a group of option p339 elements with a common label.
The element's group of option p339 elements consists of the option p339 elements that are children of the
optgroup p338 element.
When showing option p339 elements in select p334 elements, user agents should show the option p339 elements of
such groups as being related to each other and separate from other option p339 elements.
The disabled attribute is a boolean attribute p34 and can be used to disable p340 a group of option p339 elements
together.
The label attribute must be specified. Its value gives the name of the group, for the purposes of the user
interface. User agents should use this attribute's value when labelling the group of option p339 elements in a
select p334 element.
The disabled and label attributes must reflect p57 the respective content attributes of the same name.
The following snippet shows how a set of lessons from three courses could be offered in a select p334 dropdown widget:
4.10.12 The option element
Categories
None.
Contexts in which this element may be used:
As a child of a select p334 element.
As a child of a datalist p338 element.
As a child of an optgroup p338 element.
Content model:
Text p91 .
Content attributes:
Global attributes p82
disabled p340
label p340
selected p340
value p340
DOM interface:
[NamedConstructor=Option(),
NamedConstructor=Option(in DOMString text),
NamedConstructor=Option(in DOMString text, in DOMString value),
339
NamedConstructor=Option(in DOMString text, in DOMString value, in boolean
defaultSelected),
NamedConstructor=Option(in DOMString text, in DOMString value, in boolean
defaultSelected, in boolean selected)]
interface HTMLOptionElement : HTMLElement {
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute DOMString label;
attribute boolean defaultSelected;
attribute boolean selected;
attribute DOMString value;
attribute DOMString text;
readonly attribute long index;
};
The option p339 element represents p638 an option in a select p334 element or as part of a list of suggestions in a
datalist p338 element.
The disabled attribute is a boolean attribute p34 . An option p339 element is disabled if its disabled p340 attribute is
present or if it is a child of an optgroup p338 element whose disabled p339 attribute is present.
An option p339 element that is disabled p340 must prevent any click p31 events that are queued p490 on the user
interaction task source p491 from being dispatched on the element.
The label attribute provides a label for element. The label of an option p339 element is the value of the label p340
attribute, if there is one, or the textContent p31 of the element, if there isn't.
The value attribute provides a value for element. The value of an option p339 element is the value of the value p340
attribute, if there is one, or the textContent p31 of the element, if there isn't.
The selected attribute represents the default selectedness p340 of the element.
The selectedness of an option p339 element is a boolean state, initially false. If the element is disabled p340 , then
the element's selectedness p340 is always false and cannot be set to true. Except where otherwise specified, when
the element is created, its selectedness p340 must be set to true if the element has a selected p340 attribute.
Whenever an option p339 element's selected p340 attribute is added, its selectedness p340 must be set to true.
Note: The Option() p341 constructor with three or fewer arguments overrides the initial state of
the selectedness p340 state to always be false even if the third argument is true (implying that
a selected p340 attribute is to be set). The fourth argument can be used to explicitly set the
initial selectedness p340 state when using the constructor.
An option p339 element's index is the number of option p339 element that are in the same list of options p335 but that
come before it in tree order p27 . If the option p339 element is not in a list of options p335 , then the option p339
element's index p340 is zero.
This box is non-normative. Implementation requirements are given below this box.
option . selected
p341
Returns true if the element is selected, and false otherwise.
option . index p341
Returns the index of the element in its select p334 element's options p337 list.
option . form p341
Returns the element's form p297 element, if any, or null otherwise.
option . text p341
Same as textContent p31 .
option = new Option p341 ( [ text [, value [, defaultSelected [, selected ] ] ] ] )
Returns a new option p339 element.
The text argument sets the contents of the element.
340
The value argument sets the value p340 attribute.
The defaultSelected argument sets the selected p340 attribute.
The selected argument sets whether or not the element is selected. If it is omitted, even if the
defaultSelected argument is true, the element is not selected.
The disabled and label IDL attributes must reflect p57 the respective content attributes of the same name. The
defaultSelected IDL attribute must reflect p57 the selected p340 content attribute.
The value IDL attribute, on getting, must return the value of the element's value p340 content attribute, if it has
one, or else the value of the element's textContent p31 IDL attribute. On setting, the element's value p340 content
attribute must be set to the new value.
The selected IDL attribute must return true if the element's selectedness p340 is true, and false otherwise.
The index IDL attribute must return the element's index p340 .
The text IDL attribute, on getting, must return the same value as the textContent p31 IDL attribute on the
element, and on setting, must act as if the textContent p31 IDL attribute on the element had been set to the new
value.
The form IDL attribute's behavior depends on whether the option p339 element is in a select p334 element or not. If
the option p339 has a select p334 element as its parent, or has a colgroup p278 element as its parent and that
colgroup p278 element has a select p334 element as its parent, then the form p341 IDL attribute must return the same
value as the form p354 IDL attribute on that select p334 element. Otherwise, it must return null.
Several constructors are provided for creating HTMLOptionElement p340 objects (in addition to the factory methods
from DOM Core such as createElement()): Option(), Option(text), Option(text, value), Option(text,
value, defaultSelected), and Option(text, value, defaultSelected, selected). When invoked as
constructors, these must return a new HTMLOptionElement p340 object (a new option p339 element). If the text
argument is present, the new object must have as its only child a Node p31 with node type TEXT_NODE (3) whose
data is the value of that argument. If the value argument is present, the new object must have a value p340
attribute set with the value of the argument as its value. If the defaultSelected argument is present and true, the
new object must have a selected p340 attribute set with no value. If the selected argument is present and true, the
new object must have its selectedness p340 set to true; otherwise the fourth argument is absent or false, and the
selectedness p340 must be set to false, even if the defaultSelected argument is present and true. The element's
document must be the active document p439 of the browsing context p439 of the Window p443 object on which the
interface object of the invoked constructor is found.
4.10.13 The textarea element
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Listed p297 , labelable p297 , submittable p297 , and resettable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Text p91 .
Content attributes:
Global attributes p82
autofocus p354
cols p342
disabled p354
form p353
maxlength p343
name p354
placeholder p343
readonly p342
required p343
rows p343
wrap p343
341
DOM interface:
interface HTMLTextAreaElement : HTMLElement {
attribute boolean autofocus;
attribute unsigned long cols;
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute long maxLength;
attribute DOMString name;
attribute DOMString placeholder;
attribute boolean readOnly;
attribute boolean required;
attribute unsigned long rows;
attribute DOMString wrap;
readonly attribute
attribute
attribute
readonly attribute
DOMString type;
DOMString defaultValue;
DOMString value;
unsigned long textLength;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
void select();
attribute unsigned long selectionStart;
attribute unsigned long selectionEnd;
void setSelectionRange(in unsigned long start, in unsigned long end);
};
The textarea p341 element represents p638 a multiline plain text edit control for the element's raw value. The
contents of the control represent the control's default value.
The raw value p342 of a textarea p341 control must be initially the empty string.
The readonly attribute is a boolean attribute p34 used to control whether the text can be edited by the user or not.
Constraint validation: If the readonly p342 attribute is specified on a textarea p341 element, the element is barred
from constraint validation p356 .
A textarea p341 element is mutable if it is neither disabled p354 nor has a readonly p342 attribute specified.
When a textarea p341 is mutable p342 , its raw value p342 should be editable by the user. Any time the user causes the
element's raw value p342 to change, the user agent must queue a task p490 to fire a simple event p496 that bubbles
named input at the textarea p341 element, then broadcast forminput events p366 at the textarea p341 element's
form owner p353 . User agents may wait for a suitable break in the user's interaction before queuing the task; for
example, a user agent could wait for the user to have not hit a key for 100ms, so as to only fire the event when
the user pauses, instead of continuously for each keystroke.
A textarea p341 element has a dirty value flag, which must be initially set to false, and must be set to true
whenever the user interacts with the control in a way that changes the raw value p342 .
When the textarea p341 element's textContent p31 IDL attribute changes value, if the element's dirty value flag p342
is false, then the element's raw value p342 must be set to the value of the element's textContent p31 IDL attribute.
The reset algorithm p366 for textarea p341 elements is to set the element's value p342 to the value of the element's
textContent p31 IDL attribute.
The cols attribute specifies the expected maximum number of characters per line. If the cols p342 attribute is
specified, its value must be a valid non-negative integer p35 greater than zero. If applying the rules for parsing nonnegative integers p35 to the attribute's value results in a number greater than zero, then the element's character
width is that value; otherwise, it is 20.
The user agent may use the textarea p341 element's character width p342 as a hint to the user as to how many
characters the server prefers per line (e.g. for visual user agents by making the width of the control be that many
342
characters). In visual renderings, the user agent should wrap the user's input in the rendering so that each line is
no wider than this number of characters.
The rows attribute specifies the number of lines to show. If the rows p343 attribute is specified, its value must be a
valid non-negative integer p35 greater than zero. If applying the rules for parsing non-negative integers p35 to the
attribute's value results in a number greater than zero, then the element's character height is that value;
otherwise, it is 2.
Visual user agents should set the height of the control to the number of lines given by character height p343 .
The wrap attribute is an enumerated attribute p34 with two keywords and states: the soft keyword which maps to
the Soft state, and the hard keyword which maps to the Hard state. The missing value default is the Soft p343
state.
If the element's wrap p343 attribute is in the Hard p343 state, the cols p342 attribute must be specified.
The element's value p354 is defined to be the element's raw value p342 with the following transformation applied:
1.
Replace every occurrence of a U+000D CARRIAGE RETURN (CR) character not followed by a U+000A
LINE FEED (LF) character, and every occurrence of a U+000A LINE FEED (LF) character not preceded by
a U+000D CARRIAGE RETURN (CR) character, by a two-character string consisting of a U+000D
CARRIAGE RETURN U+000A LINE FEED (CRLF) character pair.
2.
If the element's wrap p343 attribute is in the Hard p343 state, insert U+000D CARRIAGE RETURN U+000A
LINE FEED (CRLF) character pairs into the string using a UA-defined algorithm so that each line has no
more than character width p342 characters. For the purposes of this requirement, lines are delimited by
the start of the string, the end of the string, and U+000D CARRIAGE RETURN U+000A LINE FEED (CRLF)
character pairs.
The maxlength attribute is a form control maxlength attribute p355 controlled by the textarea p341 element's dirty
value flag p342 .
If the textarea p341 element has a maximum allowed value length p355 , then the element's children must be such
that the code-point length p34 of the value of the element's textContent p31 IDL attribute is equal to or less than the
element's maximum allowed value length p355 .
The required attribute is a boolean attribute p34 . When specified, the user will be required to enter a value before
submitting the form.
Constraint validation: If the element has its required p343 attribute specified, and the element is mutable p342 ,
and the element's value p354 is the empty string, then the element is suffering from being missing p357 .
The placeholder attribute represents a hint (a word or short phrase) intended to aid the user with data entry. A
hint could be a sample value or a brief description of the expected format. The attribute, if specified, must have a
value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
Note: For a longer hint or other advisory text, the title p84 attribute is more appropriate.
The placeholder p343 attribute should not be used as an alternative to a label p301 .
User agents should present this hint to the user, after having stripped line breaks p34 from it, when the element's
value p354 is the empty string and the control is not focused (e.g. by displaying it inside a blank unfocused control).
The form p353 attribute is used to explicitly associate the textarea p341 element with its form owner p353 . The name p354
attribute represents the element's name. The disabled p354 attribute is used to make the control non-interactive
and to prevent its value from being submitted. The autofocus p354 attribute controls focus.
This box is non-normative. Implementation requirements are given below this box.
textarea . type
Returns the string "textarea".
textarea . value
Returns the current value of the element.
Can be set, to change the value.
The cols, placeholder, required, rows, and wrap attributes must reflect p57 the respective content attributes of
the same name. The cols p343 and rows p343 attributes are limited to only non-negative numbers greater than
zero p58 . The maxLength IDL attribute must reflect p57 the maxlength p343 content attribute, limited to only nonnegative numbers p58 . The readOnly IDL attribute must reflect p57 the readonly p342 content attribute.
343
The type IDL attribute must return the value "textarea".
The defaultValue IDL attribute must act like the element's textContent p31 IDL attribute.
The value attribute must, on getting, return the element's raw value p342 ; on setting, it must set the element's raw
value p342 to the new value.
The textLength IDL attribute must return the code-point length p34 of the element's value p354 .
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s. The select() p517 , selectionStart p517 , selectionEnd p517 , and
setSelectionRange() p517 methods and attributes expose the element's text selection.
Here is an example of a textarea p341 being used for unrestricted free-form text input in a form:
If you have any comments, please let us know:
4.10.14 The keygen element
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Listed p297 , labelable p297 , submittable p297 , and resettable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Empty.
Content attributes:
Global attributes p82
autofocus p354
challenge p344
disabled p354
form p353
keytype p344
name p354
DOM interface:
interface HTMLKeygenElement : HTMLElement {
attribute boolean autofocus;
attribute DOMString challenge;
attribute boolean disabled;
readonly attribute HTMLFormElement form;
attribute DOMString keytype;
attribute DOMString name;
readonly attribute DOMString type;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
};
The keygen p344 element represents p638 a key pair generator control. When the control's form is submitted, the
private key is stored in the local keystore, and the public key is packaged and sent to the server.
The challenge attribute may be specified. Its value will be packaged with the submitted key.
The keytype attribute is an enumerated attribute p34 . The following table lists the keywords and states for the
attribute — the keywords in the left column map to the states listed in the cell in the second column on the same
344
row as the keyword. User agents are not required to support these values, and must only recognize values whose
corresponding algorithms they support.
Keyword State
rsa
RSA
The invalid value default state is the unknown state. The missing value default state is the RSA state, if it is
supported, or the unknown state otherwise.
Note: This specification does not specify what key types user agents are to support — it is
possible for a user agent to not support any key types at all.
The user agent may expose a user interface for each keygen p344 element to allow the user to configure settings of
the element's key pair generator, e.g. the key length.
The reset algorithm p366 for keygen p344 elements is to set these various configuration settings back to their defaults.
The element's value p354 is the string returned from the following algorithm:
1.
Use the appropriate step from the following list:
p344
attribute is in the RSA state
↪ If the keytype
Generate an RSA key pair using the settings given by the user, if appropriate, using the
md5WithRSAEncryption RSA signature algorithm (the signature algorithm with MD5 and the
RSA encryption algorithm) referenced in section 2.2.1 ("RSA Signature Algorithm") of RFC
3279, and defined in RFC 2313. [RFC3279] p703 [RFC2313] p702
p344
attribute is in the unknown state
↪ Otherwise, the keytype
The given key type is not supported. Return the empty string and abort this algorithm.
Let private key be the generated private key.
Let public key be the generated public key.
Let signature algorithm be the selected signature algorithm.
2.
If the element has a challenge p344 attribute, then let challenge be that attribute's value. Otherwise, let
challenge be the empty string.
3.
Let algorithm be an ASN.1 AlgorithmIdentifier structure as defined by RFC 5280, with the algorithm
field giving the ASN.1 OID used to identify signature algorithm, using the OIDs defined in section 2.2
("Signature Algorithms") of RFC 3279, and the parameters field set up as required by RFC 3279 for
AlgorithmIdentifier structures for that algorithm. [X690] p705 [RFC5280] p703 [RFC3279] p703
4.
Let spki be an ASN.1 SubjectPublicKeyInfo structure as defined by RFC 5280, with the algorithm field
set to the algorithm structure from the previous step, and the subjectPublicKey field set to the BIT
STRING value resulting from ASN.1 DER encoding the public key. [X690] p705 [RFC5280] p703
5.
Let publicKeyAndChallenge be an ASN.1 PublicKeyAndChallenge p345 structure as defined below, with
the spki field set to the spki structure from the previous step, and the challenge field set to the string
challenge obtained earlier. [X690] p705
6.
Let signature be the BIT STRING value resulting from ASN.1 DER encoding the signature generated by
applying the signature algorithm to the byte string obtained by ASN.1 DER encoding the
publicKeyAndChallenge structure, using private key as the signing key. [X690] p705
7.
Let signedPublicKeyAndChallenge be an ASN.1 SignedPublicKeyAndChallenge p345 structure as defined
below, with the publicKeyAndChallenge field set to the publicKeyAndChallenge structure, the
signatureAlgorithm field set to the algorithm structure, and the signature field set to the BIT STRING
signature from the previous step. [X690] p705
8.
Return the result of base64 encoding the result of ASN.1 DER encoding the
signedPublicKeyAndChallenge structure. [RFC3548] p703 [X690] p705
The data objects used by the above algorithm are defined as follows. These definitions use the same "ASN.1-like"
syntax defined by RFC 5280. [RFC5280] p703
PublicKeyAndChallenge ::= SEQUENCE {
spki SubjectPublicKeyInfo,
challenge IA5STRING
}
SignedPublicKeyAndChallenge ::= SEQUENCE {
345
publicKeyAndChallenge PublicKeyAndChallenge,
signatureAlgorithm AlgorithmIdentifier,
signature BIT STRING
}
Constraint validation: The keygen p344 element is barred from constraint validation p356 .
The form p353 attribute is used to explicitly associate the keygen p344 element with its form owner p353 . The name p354
attribute represents the element's name. The disabled p354 attribute is used to make the control non-interactive
and to prevent its value from being submitted. The autofocus p354 attribute controls focus.
This box is non-normative. Implementation requirements are given below this box.
keygen . type
Returns the string "keygen".
The challenge IDL attribute must reflect p57 the content attributes of the same name.
The keytype IDL attribute must reflect p57 the content attributes of the same name, limited to only known
values p58 .
The type IDL attribute must return the value "keygen".
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s.
Note: This specification does not specify how the private key generated is to be used. It is
expected that after receiving the SignedPublicKeyAndChallenge p345 (SPKAC) structure, the
server will generate a client certificate and offer it back to the user for download; this
certificate, once downloaded and stored in the key store along with the private key, can then
be used to authenticate to services that use SSL and certificate authentication.
To generate a key pair, add the private key to the user's key store, and submit the public key to the server,
markup such as the following can be used:
The server will then receive a form submission with a packaged RSA public key as the value of "key". This
can then be used for various purposes, such as generating a client certificate, as mentioned above.
4.10.15 The output element
Categories
Flow content p91 .
Phrasing content p91 .
Listed p297 , labelable p297 , and resettable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
for p347
form p353
name p354
DOM interface:
interface HTMLOutputElement : HTMLElement {
[PutForwards=value] readonly attribute DOMSettableTokenList htmlFor;
346
readonly attribute HTMLFormElement form;
attribute DOMString name;
readonly attribute DOMString type;
attribute DOMString defaultValue;
attribute DOMString value;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(in DOMString error);
readonly attribute NodeList labels;
};
The output p346 element represents p638 the result of a calculation.
The for content attribute allows an explicit relationship to be made between the result of a calculation and the
elements that represent the values that went into the calculation or that otherwise influenced the calculation. The
for p347 attribute, if specified, must contain a string consisting of an unordered set of unique space-separated
tokens p49 , each of which must have the value of an ID of an element in the same Document p31 .
The form p353 attribute is used to explicitly associate the output p346 element with its form owner p353 . The name p354
attribute represents the element's name.
The element has a value mode flag which is either value or default. Initially, the value mode flag p347 must be set
to default.
When the value mode flag p347 is in mode default, the contents of the element represent both the value of the
element and its default value. When the value mode flag p347 is in mode value, the contents of the element
represent the value of the element only, and the default value is only accessible using the defaultValue p347 IDL
attribute.
The element also has a default value. Initially, the default value p347 must be the empty string.
Whenever the element's descendants are changed in any way, if the value mode flag p347 is in mode default, the
element's default value p347 must be set to the value of the element's textContent p31 IDL attribute.
The reset algorithm p366 for output p346 elements is to set the element's textContent p31 IDL attribute to the value of
the element's defaultValue p347 IDL attribute (thus replacing the element's child nodes), and then to set the
element's value mode flag p347 to default.
This box is non-normative. Implementation requirements are given below this box.
output . value
p347
[ = value ]
Returns the element's current value.
Can be set, to change the value.
output . defaultValue p347 [ = value ]
Returns the element's current default value.
Can be set, to change the default value.
output . type p347
Returns the string "output".
The value IDL attribute must act like the element's textContent p31 IDL attribute, except that on setting, in
addition, before the child nodes are changed, the element's value mode flag p347 must be set to value.
The defaultValue IDL attribute, on getting, must return the element's default value p347 . On setting, the attribute
must set the element's default value p347 , and, if the element's value mode flag p347 is in the mode default, set the
element's textContent p31 IDL attribute as well.
The type attribute must return the string "output".
The htmlFor IDL attribute must reflect p57 the for p347 content attribute.
347
The willValidate p358 , validity p359 , and validationMessage p359 attributes, and the checkValidity() p359 and
setCustomValidity() p358 methods, are part of the constraint validation API p358 . The labels p303 attribute provides
a list of the element's label p301 s.
Constraint validation: output p346 elements are always barred from constraint validation p356 .
A simple calculator could use output p346 for its display of calculated results:
4.10.16 The progress element
Categories
Flow content p91 .
Phrasing content p91 .
Labelable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but there must be no progress p348 element descendants.
Content attributes:
Global attributes p82
value p348
max p348
form p353
DOM interface:
interface HTMLProgressElement : HTMLElement {
attribute float value;
attribute float max;
readonly attribute float position;
readonly attribute HTMLFormElement form;
readonly attribute NodeList labels;
};
The progress p348 element represents p638 the completion progress of a task. The progress is either indeterminate,
indicating that progress is being made but that it is not clear how much more work remains to be done before the
task is complete (e.g. because the task is waiting for a remote host to respond), or the progress is a number in the
range zero to a maximum, giving the fraction of work that has so far been completed.
There are two attributes that determine the current task completion represented by the element.
The value attribute specifies how much of the task has been completed, and the max attribute specifies how much
work the task requires in total. The units are arbitrary and not specified.
Authors are encouraged to also include the current value and the maximum value inline as text inside the
element, so that the progress is made available to users of legacy user agents.
Here is a snippet of a Web application that shows the progress of some automated task:
Task Progress
Progress: 0 %
(The updateProgress() method in this example would be called by some other code on the page to update
the actual progress bar as the task progressed.)
348
The value p348 and max p348 attributes, when present, must have values that are valid floating point numbers p36 . The
value p348 attribute, if present, must have a value equal to or greater than zero, and less than or equal to the value
of the max p348 attribute, if present, or 1.0, otherwise. The max p348 attribute, if present, must have a value greater
than zero.
Note: The progress p348 element is the wrong element to use for something that is just a gauge,
as opposed to task progress. For instance, indicating disk space usage using progress p348
would be inappropriate. Instead, the meter p349 element is available for such use cases.
User agent requirements: If the value p348 attribute is omitted, then the progress bar is an indeterminate
progress bar. Otherwise, it is a determinate progress bar.
If the progress bar is a determinate progress bar and the element has a max p348 attribute, the user agent must
parse the max p348 attribute's value according to the rules for parsing floating point number values p36 . If this does
not result in an error, and if the parsed value is greater than zero, then the maximum value of the progress bar is
that value. Otherwise, if the element has no max p348 attribute, or if it has one but parsing it resulted in an error, or
if the parsed value was less than or equal to zero, then the maximum value of the progress bar is 1.0.
If the progress bar is a determinate progress bar, user agents must parse the value p348 attribute's value according
to the rules for parsing floating point number values p36 . If this does not result in an error, and if the parsed value is
less than the maximum value and greater than zero, then the current value of the progress bar is that parsed
value. Otherwise, if the parsed value was greater than or equal to the maximum value, then the current value of
the progress bar is the maximum value of the progress bar. Otherwise, if parsing the value p348 attribute's value
resulted in an error, or a number less than or equal to zero, then the current value of the progress bar is zero.
UA requirements for showing the progress bar: When representing a progress p348 element to the user, the
UA should indicate whether it is a determinate or indeterminate progress bar, and in the former case, should
indicate the relative position of the current value relative to the maximum value.
The max and value IDL attributes must reflect p57 the respective content attributes of the same name. When the
relevant content attributes are absent, the IDL attributes must return zero.
The form p353 attribute is used to explicitly associate the progress p348 element with its form owner p353 .
This box is non-normative. Implementation requirements are given below this box.
progress . position
p349
For a determinate progress bar (one with known current and maximum values), returns the result of
dividing the current value by the maximum value.
For an indeterminate progress bar, returns −1.
If the progress bar is an indeterminate progress bar, then the position IDL attribute must return −1. Otherwise, it
must return the result of dividing the current value by the maximum value.
The labels p303 attribute provides a list of the element's label p301 s.
4.10.17 The meter element
Categories
Flow content p91 .
Phrasing content p91 .
Labelable p297 form-associated element p297 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Phrasing content p91 , but there must be no meter p349 element descendants.
Content attributes:
Global attributes p82
value p350
min p350
max p350
low p350
high p350
optimum p350
form p353
349
DOM interface:
interface HTMLMeterElement : HTMLElement {
attribute float value;
attribute float min;
attribute float max;
attribute float low;
attribute float high;
attribute float optimum;
readonly attribute HTMLFormElement form;
readonly attribute NodeList labels;
};
The meter p349 element represents p638 a scalar measurement within a known range, or a fractional value; for
example disk usage, the relevance of a query result, or the fraction of a voting population to have selected a
particular candidate.
This is also known as a gauge.
Note: The meter p349 element should not be used to indicate progress (as in a progress bar). For
that role, HTML provides a separate progress p348 element.
Note: The meter p349 element also does not represent a scalar value of arbitrary range — for
example, it would be wrong to use this to report a weight, or height, unless there is a known
maximum value.
There are six attributes that determine the semantics of the gauge represented by the element.
The min attribute specifies the lower bound of the range, and the max attribute specifies the upper bound. The
value attribute specifies the value to have the gauge indicate as the "measured" value.
The other three attributes can be used to segment the gauge's range into "low", "medium", and "high" parts, and
to indicate which part of the gauge is the "optimum" part. The low attribute specifies the range that is considered
to be the "low" part, and the high attribute specifies the range that is considered to be the "high" part. The
optimum attribute gives the position that is "optimum"; if that is higher than the "high" value then this indicates
that the higher the value, the better; if it's lower than the "low" mark then it indicates that lower values are better,
and naturally if it is in between then it indicates that neither high nor low values are good.
Authoring requirements: The value p350 attribute must be specified. The value p350 , min p350 , low p350 , high p350 ,
max p350 , and optimum p350 attributes, when present, must have values that are valid floating point numbers p36 .
In addition, the attributes' values are further constrained:
Let value be the value p350 attribute's number.
If the min p350 attribute attribute is specified, then let minimum be that attribute's value; otherwise, let it be zero.
If the max p350 attribute attribute is specified, then let maximum be that attribute's value; otherwise, let it be 1.0.
The following inequalities must hold, as applicable:
•
•
•
•
•
minimum ≤ value ≤ maximum
minimum ≤ low p350 ≤ maximum (if low p350 is specified)
minimum ≤ high p350 ≤ maximum (if high p350 is specified)
minimum ≤ optimum p350 ≤ maximum (if optimum p350 is specified)
low p350 ≤ high p350 (if both low p350 and high p350 are specified)
Note: If no minimum or maximum is specified, then the range is assumed to be 0..1, and the
value thus has to be within that range.
Authors are encouraged to include a textual representation of the gauge's state in the element's contents, for
users of user agents that do not support the meter p349 element.
The following examples show three gauges that would all be three-quarters full:
Storage space usage: 6 blocks used (out of 8 total)
Voter turnout: The grapefruit pie had a radius of 12cm
and a height of 2cm .
Instead, one would either not include the meter element, or use the meter element with a defined range to
give the dimensions in context compared to other pies:
The grapefruit pie had a radius of 12cm and a height of
2cm.
Radius: 12cm
Height: 2cm
There is no explicit way to specify units in the meter p349 element, but the units may be specified in the title p84
attribute in free-form text.
The example above could be extended to mention the units:
Radius: 12cm
Height: 2cm
User agent requirements: User agents must parse the min p350 , max p350 , value p350 , low p350 , high p350 , and
optimum p350 attributes using the rules for parsing floating point number values p36 .
User agents must then use all these numbers to obtain values for six points on the gauge, as follows. (The order in
which these are evaluated is important, as some of the values refer to earlier ones.)
The minimum value
If the min p350 attribute is specified and a value could be parsed out of it, then the minimum value is that
value. Otherwise, the minimum value is zero.
The maximum value
If the max p350 attribute is specified and a value could be parsed out of it, the maximum value is that value.
Otherwise, the maximum value is 1.0.
If the maximum value would be less than the minimum value, then the maximum value is actually the same
as the minimum value.
The actual value
If the value p350 attribute is specified and a value could be parsed out of it, then that value is the actual
value. Otherwise, the actual value is zero.
If the actual value would be less than the minimum value, then the actual value is actually the same as the
minimum value.
If, on the other hand, the actual value would be greater than the maximum value, then the actual value is
the maximum value.
The low boundary
If the low p350 attribute is specified and a value could be parsed out of it, then the low boundary is that value.
Otherwise, the low boundary is the same as the minimum value.
If the low boundary is then less than the minimum value, then the low boundary is actually the same as the
minimum value. Similarly, if the low boundary is greater than the maximum value, then it is actually the
maximum value instead.
The high boundary
If the high p350 attribute is specified and a value could be parsed out of it, then the high boundary is that
value. Otherwise, the high boundary is the same as the maximum value.
If the high boundary is then less than the low boundary, then the high boundary is actually the same as the
low boundary. Similarly, if the high boundary is greater than the maximum value, then it is actually the
maximum value instead.
The optimum point
If the optimum p350 attribute is specified and a value could be parsed out of it, then the optimum point is that
value. Otherwise, the optimum point is the midpoint between the minimum value and the maximum value.
351
If the optimum point is then less than the minimum value, then the optimum point is actually the same as
the minimum value. Similarly, if the optimum point is greater than the maximum value, then it is actually the
maximum value instead.
All of which will result in the following inequalities all being true:
•
•
•
minimum value ≤ actual value ≤ maximum value
minimum value ≤ low boundary ≤ high boundary ≤ maximum value
minimum value ≤ optimum point ≤ maximum value
UA requirements for regions of the gauge: If the optimum point is equal to the low boundary or the high
boundary, or anywhere in between them, then the region between the low and high boundaries of the gauge must
be treated as the optimum region, and the low and high parts, if any, must be treated as suboptimal. Otherwise, if
the optimum point is less than the low boundary, then the region between the minimum value and the low
boundary must be treated as the optimum region, the region between the low boundary and the high boundary
must be treated as a suboptimal region, and the region between the high boundary and the maximum value must
be treated as an even less good region. Finally, if the optimum point is higher than the high boundary, then the
situation is reversed; the region between the high boundary and the maximum value must be treated as the
optimum region, the region between the high boundary and the low boundary must be treated as a suboptimal
region, and the remaining region between the low boundary and the minimum value must be treated as an even
less good region.
UA requirements for showing the gauge: When representing a meter p349 element to the user, the UA should
indicate the relative position of the actual value to the minimum and maximum values, and the relationship
between the actual value and the three regions of the gauge.
The following markup:
Suggested groups
Hide suggested groups
Might be rendered as follows:
User agents may combine the value of the title p84 attribute and the other attributes to provide context-sensitive
help or inline text detailing the actual values.
352
For example, the following snippet:
Disk usage: 170 261 928 bytes used
out of 233 257 824 bytes available
4.10.18 Association of controls and forms
A form-associated element p297 can have a relationship with a form p297 element, which is called the element's form
owner. If a form-associated element p297 is not associated with a form p297 element, its form owner p353 is said to be
null.
A form-associated element p297 is, by default, associated with its nearest ancestor form p297 element (as described
below), but may have a form attribute specified to override this.
If a form-associated element p297 has a form p353 attribute specified, then its value must be the ID of a form p297
element in the element's owner Document p31 .
When a form-associated element p297 is created, its form owner p353 must be initialized to null (no owner).
When a form-associated element p297 is to be associated with a form, its form owner p353 must be set to that form.
When a form-associated element p297 's ancestor chain changes, e.g. because it or one of its ancestors was
inserted p27 or removed p27 from a Document p31 , then the user agent must reset the form owner p353 of that element.
When a form-associated element p297 's form p353 attribute is added, removed, or has its value changed, then the
user agent must reset the form owner p353 of that element.
When a form-associated element p297 has a form p353 attribute and the ID of any of the elements in the Document p31
changes, then the user agent must reset the form owner p353 of that form-associated element p297 .
When a form-associated element p297 has a form p353 attribute and an element with an ID is inserted into p27 or
removed from p27 the Document p31 , then the user agent must reset the form owner p353 of that form-associated
element p297 .
When the user agent is to reset the form owner of a form-associated element p297 , it must run the following
steps:
1.
If the element's form owner p353 is not null, and the element's form p353 content attribute is not present,
and the element's form owner p353 is its nearest form p297 element ancestor after the change to the
ancestor chain, then do nothing, and abort these steps.
2.
Let the element's form owner p353 be null.
3.
If the element has a form p353 content attribute, then run these substeps:
1.
If the first element in the Document p27 to have an ID that is case-sensitively p33 equal to the
element's form p353 content attribute's value is a form p297 element, then associate p353 the formassociated element p297 with that form p297 element.
2.
Abort the "reset the form owner" steps.
4.
Otherwise, if the form-associated element p297 in question has an ancestor form p297 element, then
associate p353 the form-associated element p297 with the nearest such ancestor form p297 element.
5.
Otherwise, the element is left unassociated.
In the following non-conforming snippet:
...
...
The form owner p353 of "d" would be the inner nested form "c", while the form owner p353 of "e" would be the
outer form "a".
This is because despite the association of "e" with "c" in the HTML parser p554 , when the innerHTML p102
algorithm moves the nodes from the temporary document to the "b" element, the nodes see their ancestor
chain change, and thus all the "magic" associations done by the parser are reset to normal ancestor
associations.
This example is a non-conforming document, though, as it is a violation of the content models to nest
form p297 elements.
This box is non-normative. Implementation requirements are given below this box.
element . form
p354
Returns the element's form owner p353 .
Returns null if there isn't one.
Form-associated elements p297 have a form IDL attribute, which, on getting, must return the element's form
owner p353 , or null if there isn't one.
4.10.19 Attributes common to form controls
4.10.19.1 Naming form controls
The name content attribute gives the name of the form control, as used in form submission p360 and in the form p297
element's elements p299 object. If the attribute is specified, its value must not be the empty string.
The name IDL attribute must reflect p57 the name p354 content attribute.
4.10.19.2 Enabling and disabling form controls
The disabled content attribute is a boolean attribute p34 .
A form control is disabled if its disabled p354 attribute is set, or if it is a descendant of a fieldset p300 element
whose disabled p300 attribute is set and is not a descendant of that fieldset p300 element's first legend p301
element child, if any.
A form control that is disabled p354 must prevent any click p31 events that are queued p490 on the user interaction
task source p491 from being dispatched on the element.
Constraint validation: If an element is disabled p354 , it is barred from constraint validation p356 .
The disabled IDL attribute must reflect p57 the disabled p354 content attribute.
4.10.19.3 A form control's value
Form controls have a value and a checkedness. (The latter is only used by input p303 elements.) These are used
to describe how the user interacts with the control.
4.10.19.4 Autofocusing a form control
The autofocus content attribute allows the user to indicate that a control is to be focused as soon as the page is
loaded, allowing the user to just start typing without having to manually focus the main control.
The autofocus p354 attribute is a boolean attribute p34 .
There must not be more than one element in the document with the autofocus p354 attribute specified.
Whenever an element with the autofocus p354 attribute specified is inserted into a document p27 whose browsing
context p439 did not have the sandboxed automatic features browsing context flag p203 set when the Document p31
354
was created, the user agent should queue a task p490 that checks to see if the element is focusable p510 , and if so,
runs the focusing steps p511 for that element. User agents may also change the scrolling position of the document,
or perform some other action that brings the element to the user's attention. The task source p490 for this task is
the DOM manipulation task source p491 .
User agents may ignore this attribute if the user has indicated (for example, by starting to type in a form control)
that he does not wish focus to be changed.
Note: Focusing the control does not imply that the user agent must focus the browser window
if it has lost focus.
The autofocus IDL attribute must reflect p57 the content attribute of the same name.
In the following snippet, the text control would be focused when the document was loaded.
Feeling:
The validity attribute must return a ValidityState p359 object that represents the validity states p356 of the
element. This object is live p27 , and the same object must be returned each time the element's validity p359
attribute is retrieved.
interface ValidityState {
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
readonly attribute boolean
};
valueMissing;
typeMismatch;
patternMismatch;
tooLong;
rangeUnderflow;
rangeOverflow;
stepMismatch;
customError;
valid;
A ValidityState p359 object has the following attributes. On getting, they must return true if the corresponding
condition given in the following list is true, and false otherwise.
valueMissing
The control is suffering from being missing p357 .
typeMismatch
The control is suffering from a type mismatch p357 .
patternMismatch
The control is suffering from a pattern mismatch p357 .
tooLong
The control is suffering from being too long p357 .
rangeUnderflow
The control is suffering from an underflow p357 .
rangeOverflow
The control is suffering from an overflow p357 .
stepMismatch
The control is suffering from a step mismatch p357 .
customError
The control is suffering from a custom error p357 .
valid
None of the other conditions are true.
When the checkValidity() method is invoked, if the element is a candidate for constraint validation p356 and does
not satisfy its constraints p357 , the user agent must fire a simple event p496 named invalid that is cancelable (but in
this case has no default action) at the element and return false. Otherwise, it must only return true without doing
anything else.
The validationMessage attribute must return the empty string if the element is not a candidate for constraint
validation p356 or if it is one but it satisfies its constraints p357 ; otherwise, it must return a suitably localized message
that the user agent would show the user if this were the only form control with a validity constraint problem. If the
user agent would not actually show a textual message in such a situation (e.g. it would show a graphical cue
instead), then the attribute must return a suitably localized message that expresses (one or more of) the validity
359
constraint(s) that the control does not satisfy. If the element is a candidate for constraint validation p356 and is
suffering from a custom error p357 , then the custom validity error message p356 should be present in the return value.
4.10.20.4 Security
Servers should not rely on client-side validation. Client-side validation can be intentionally bypassed by hostile
users, and unintentionally bypassed by users of older user agents or automated tools that do not implement these
features. The constraint validation features are only intended to improve the user experience, not to provide any
kind of security mechanism.
4.10.21 Form submission
4.10.21.1 Introduction
This section is non-normative.
When forms are submitted, the data in the form is converted into the form specified by the enctype p356 , and then
sent to the destination specified by the action p355 using the given method p355 .
For example, take the following form:
If the user types in "cats" in the first field and "fur" in the second, and then hits the submit button, then the user
agent will load /find.cgi?t=cats&q=fur.
On the other hand, consider this form:
Given the same user input, the result on submission is quite different: the user agent instead does an HTTP POST
to the given URL, with as the entity body something like the following text:
------kYFrd4jNJEgCervE
Content-Disposition: form-data; name="t"
cats
------kYFrd4jNJEgCervE
Content-Disposition: form-data; name="q"
fur
------kYFrd4jNJEgCervE--
4.10.21.2 Implicit submission
User agents may establish a button p297 in each form as being the form's default button. This should be the first
submit button p297 in tree order p27 whose form owner p353 is that form p297 element, but user agents may pick another
button if another would be more appropriate for the platform. If the platform supports letting the user submit a
form implicitly (for example, on some platforms hitting the "enter" key while a text field is focused implicitly
submits the form), then doing so must cause the form's default button p360 's activation behavior p93 , if any, to be
run.
Note: Consequently, if the default button p360 is disabled p354 , the form is not submitted when
such an implicit submission mechanism is used. (A button has no activation behavior p93 when
disabled.)
If the form has no submit button p297 , then the implicit submission mechanism must just submit p361 the form p297
element from the form p297 element itself.
360
4.10.21.3 Form submission algorithm
When a form form is submitted from an element submitter (typically a button), optionally with a scripted-submit
flag set, the user agent must run the following steps:
1.
If form is in a Document p31 that has no associated browsing context p439 or whose browsing context p439
had its sandboxed forms browsing context flag p203 set when the Document p31 was created, then abort
these steps without doing anything.
2.
If form is already being submitted (i.e. the form was submitted p361 again while processing the events
fired from the next two steps, probably from a script redundantly calling the submit() p299 method on
form), then abort these steps. This doesn't affect the earlier instance of this algorithm.
3.
If the scripted-submit flag is not set, and the submitter element's no-validate state p356 is false, then
interactively validate the constraints p357 of form and examine the result: if the result is negative (the
constraint validation concluded that there were invalid fields and probably informed the user of this)
then abort these steps.
4.
If the scripted-submit flag is not set, then fire a simple event p496 that is cancelable named submit, at
form. If the event's default action is prevented (i.e. if the event is canceled) then abort these steps.
Otherwise, continue (effectively the default action is to perform the submission).
5.
Let controls be a list of all the submittable elements p297 whose form owner p353 is form, in tree order p27 .
6.
Let the form data set be a list of name-value-type tuples, initially empty.
7.
Constructing the form data set. For each element field in controls, in tree order p27 , run the following
substeps:
1.
If any of the following conditions are met, then skip these substeps for this element:
•
The field element has a datalist p338 element ancestor.
•
The field element is disabled p354 .
•
The field element is a button p297 but it is not submitter.
•
The field element is an input p303 element whose type p304 attribute is in the
Checkbox p318 state and whose checkedness p354 is false.
•
The field element is an input p303 element whose type p304 attribute is in the Radio
Button p319 state and whose checkedness p354 is false.
•
The field element is not an input p303 element whose type p304 attribute is in the
Image Button p321 state, and either the field element does not have a name p354
attribute specified, or its name p354 attribute's value is the empty string.
•
The field element is an object p208 element that is not using a plugin p27 .
Otherwise, process field as follows:
2.
Let type be the value of the type IDL attribute of field.
3.
If the field element is an input p303 element whose type p304 attribute is in the Image Button p321
state, then run these further nested substeps:
1.
If the field element has an name p354 attribute specified and value is not the empty
string, let name be that value followed by a single U+002E FULL STOP character (.).
Otherwise, let name be the empty string.
2.
Let namex be the string consisting of the concatenation of name and a single
U+0078 LATIN SMALL LETTER X character (x).
3.
Let namey be the string consisting of the concatenation of name and a single
U+0079 LATIN SMALL LETTER Y character (y).
4.
The field element is submitter, and before this algorithm was invoked the user
indicated a coordinate p322 . Let x be the x-component of the coordinate selected by
the user, and let y be the y-component of the coordinate selected by the user.
5.
Append an entry in the form data set with the name namex, the value x, and the
type type.
6.
Append an entry in the form data set with the name namey and the value y, and the
type type.
361
7.
Skip the remaining substeps for this element: if there are any more elements in
controls, return to the top of the constructing the form data set p361 step, otherwise,
jump to the next step in the overall form submission algorithm.
4.
Let name be the value of the field element's name p354 attribute.
5.
If the field element is a select p334 element, then for each option p339 element in the select p334
element whose selectedness p340 is true, append an entry in the form data set with the name
as the name, the value p340 of the option p339 element as the value, and type as the type.
6.
Otherwise, if the field element is an input p303 element whose type p304 attribute is in the
Checkbox p318 state or the Radio Button p319 state, then run these further nested substeps:
1.
If the field element has a value p306 attribute specified, then let value be the value of
that attribute; otherwise, let value be the string "on".
2.
Append an entry in the form data set with name as the name, value as the value,
and type as the type.
7.
Otherwise, if the field element is an input p303 element whose type p304 attribute is in the File
Upload p320 state, then for each file selected p320 in the input p303 element, append an entry in
the form data set with the name as the name, the file (consisting of the name, the type, and
the body) as the value, and type as the type. If there are no selected files p320 , then append an
entry in the form data set with the name as the name, the empty string as the value, and
application/octet-stream as the type.
8.
Otherwise, if the field element is an object p208 element: try to obtain a form submission value
from the plugin p27 , and if that is successful, append an entry in the form data set with name as
the name, the returned form submission value as the value, and the string "object" as the
type.
9.
Otherwise, append an entry in the form data set with name as the name, the value p354 of the
field element as the value, and type as the type.
8.
Let action be the submitter element's action p355 .
9.
If action is the empty string, let action be the document's address p71 .
Note: This step is a willful violation p17 of RFC 3986, which would require base URL
processing here. This violation is motivated by a desire for compatibility with legacy
content. [RFC3986] p703
10.
Resolve p51 the URL p51 action, relative to the submitter element. If this fails, abort these steps. Otherwise,
let action be the resulting absolute URL p52 .
11.
Let scheme be the p51 of the resulting absolute URL p52 .
12.
Let enctype be the submitter element's enctype p356 .
13.
Let method be the submitter element's method p355 .
14.
Let target be the submitter element's target p356 .
15.
Select the appropriate row in the table below based on the value of scheme as given by the first cell of
each row. Then, select the appropriate cell on that row based on the value of method as given in the
first cell of each column. Then, jump to the steps named in that cell and defined below the table.
GET p355
POST p355
p363
PUT p355
p363
DELETE p355
p363
Delete action p363
http
Mutate action
https
Mutate action p363
Submit as entity body p363 Submit as entity body p363 Delete action p363
ftp
Get action p363
Get action p363
Get action p363
Get action p363
javascript Get action
p363
p363
p363
Get action p363
data
p363
mailto
Get action
Mail with headers
Submit as entity body
Get action
p364
Post to data:
p363
Mail as body
p364
Submit as entity body
Get action
Put to data:
p364
Mail with headers
Get action p363
p364
Mail with headers p364
If scheme is not one of those listed in this table, then the behavior is not defined by this specification.
User agents should, in the absence of another specification defining this, act in a manner analogous to
that defined in this specification for similar schemes.
The behaviors are as follows:
362
Mutate action
Let query be the result of encoding the form data set using the application/x-www-formurlencoded encoding algorithm p365 , interpreted as a US-ASCII string.
Let destination be a new URL p51 that is equal to the action except that its p51 component
is replaced by query (adding a U+003F QUESTION MARK character (?) if appropriate).
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to destination. If target browsing context was newly created
for this purpose by the steps above, then it must be navigated with replacement enabled p466 .
Submit as entity body
Let entity body be the result of encoding the form data set using the appropriate form encoding
algorithm p364 .
Let target browsing context be the form submission target browsing context p364 .
Let MIME type be determined as follows:
If enctype is application/x-www-form-urlencoded p356
Let MIME type be "application/x-www-form-urlencoded".
If enctype is multipart/form-data p356
Let MIME type be "multipart/form-data".
If enctype is text/plain p356
Let MIME type be "text/plain".
If method is anything but GET or POST, and the origin p449 of action is not the same origin p451 as
that of the form p297 element's Document p31 , then abort these steps.
Otherwise, navigate p459 target browsing context to action using the HTTP method given by method
and with entity body as the entity body, of type MIME type. If target browsing context was newly
created for this purpose by the steps above, then it must be navigated with replacement
enabled p466 .
Delete action
Let target browsing context be the form submission target browsing context p364 .
If the origin p449 of action is not the same origin p451 as that of the form p297 element's Document p31 ,
then abort these steps.
Otherwise, navigate p459 target browsing context to action using the DELETE method. If target
browsing context was newly created for this purpose by the steps above, then it must be
navigated with replacement enabled p466 .
Get action
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to action. If target browsing context was newly created for
this purpose by the steps above, then it must be navigated with replacement enabled p466 .
Post to data:
Let data be the result of encoding the form data set using the appropriate form encoding
algorithm p364 .
If action contains the string "%%%%" (four U+0025 PERCENT SIGN characters), then %-escape all
bytes in data that, if interpreted as US-ASCII, do not match the unreserved production in the URI
Generic Syntax, and then, treating the result as a US-ASCII string, further %-escape all the U+0025
PERCENT SIGN characters in the resulting string and replace the first occurrence of "%%%%" in action
with the resulting double-escaped string. [RFC3986] p703
Otherwise, if action contains the string "%%" (two U+0025 PERCENT SIGN characters in a row, but
not four), then %-escape all characters in data that, if interpreted as US-ASCII, do not match the
unreserved production in the URI Generic Syntax, and then, treating the result as a US-ASCII
string, replace the first occurrence of "%%" in action with the resulting escaped string.
[RFC3986] p703
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to the potentially modified action. If target browsing context
was newly created for this purpose by the steps above, then it must be navigated with
replacement enabled p466 .
363
Put to data:
Let data be the result of encoding the form data set using the appropriate form encoding
algorithm p364 .
Let MIME type be determined as follows:
If enctype is application/x-www-form-urlencoded p356
Let MIME type be "application/x-www-form-urlencoded".
If enctype is multipart/form-data p356
Let MIME type be "multipart/form-data".
If enctype is text/plain p356
Let MIME type be "text/plain".
Let destination be the result of concatenating the following:
1.
2.
3.
4.
The string "data:".
The value of MIME type.
The string ";base64,".
A base-64 encoded representation of data. [RFC2045] p702
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to destination. If target browsing context was newly created
for this purpose by the steps above, then it must be navigated with replacement enabled p466 .
Mail with headers
Let headers be the resulting encoding the form data set using the application/x-www-formurlencoded encoding algorithm p365 , interpreted as a US-ASCII string.
Replace occurrences of U+002B PLUS SIGN characters (+) in headers with the string "%20".
Let destination consist of all the characters from the first character in action to the character
immediately before the first U+003F QUESTION MARK character (?), if any, or the end of the string
if there are none.
Append a single U+003F QUESTION MARK character (?) to destination.
Append headers to destination.
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to destination. If target browsing context was newly created
for this purpose by the steps above, then it must be navigated with replacement enabled p466 .
Mail as body
Let body be the resulting encoding the form data set using the appropriate form encoding
algorithm p364 and then %-escaping all the bytes in the resulting byte string that, when interpreted
as US-ASCII, do not match the unreserved production in the URI Generic Syntax. [RFC3986] p703
Let destination have the same value as action.
If destination does not contain a U+003F QUESTION MARK character (?), append a single U+003F
QUESTION MARK character (?) to destination. Otherwise, append a single U+0026 AMPERSAND
character (&).
Append the string "body=" to destination.
Append body, interpreted as a US-ASCII string, to destination.
Let target browsing context be the form submission target browsing context p364 .
Navigate p459 target browsing context to destination. If target browsing context was newly created
for this purpose by the steps above, then it must be navigated with replacement enabled p466 .
The form submission target browsing context is obtained, when needed by the behaviors
described above, as follows: If the user indicated a specific browsing context p439 to use when submitting
the form, then that is the target browsing context. Otherwise, apply the rules for choosing a browsing
context given a browsing context name p442 using target as the name and the browsing context p439 of
form as the context in which the algorithm is executed; the resulting browsing context p439 is the target
browsing context.
The appropriate form encoding algorithm is determined as follows:
If enctype is application/x-www-form-urlencoded p356
Use the application/x-www-form-urlencoded encoding algorithm p365 .
364
If enctype is multipart/form-data p356
Use the multipart/form-data encoding algorithm p366 .
If enctype is text/plain p356
Use the text/plain encoding algorithm p366 .
4.10.21.4 URL-encoded form data
The application/x-www-form-urlencoded encoding algorithm is as follows:
1.
Let result be the empty string.
2.
If the form p297 element has an accept-charset p298 attribute, then, taking into account the characters
found in the form data set's names and values, and the character encodings supported by the user
agent, select a character encoding from the list given in the form p297 's accept-charset p298 attribute that
is an ASCII-compatible character encoding p28 . If none of the encodings are supported, then let the
selected character encoding be UTF-8.
Otherwise, if the document's character encoding p75 is an ASCII-compatible character encoding p28 , then
that is the selected character encoding.
Otherwise, let the selected character encoding be UTF-8.
3.
Let charset be the preferred MIME name p28 of the selected character encoding.
4.
For each entry in the form data set, perform these substeps:
1.
If the entry's name is "_charset_" and its type is "hidden", replace its value with charset.
2.
If the entry's type is "file", replace its value with the file's filename only.
3.
For each character in the entry's name and value that cannot be expressed using the selected
character encoding, replace the character by a string consisting of a U+0026 AMPERSAND
character (&), a U+0023 NUMBER SIGN character (#), one or more characters in the range
U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9) representing the Unicode code point of the
character in base ten, and finally a U+003B SEMICOLON character (;).
4.
For each character in the entry's name and value, apply the appropriate subsubsteps from the
following list:
↪ The character is a U+0020 SPACE character
Replace the character with a single U+002B PLUS SIGN character (+).
↪ If the character isn't in the range U+0020, U+002A, U+002D, U+002E, U+0030
to U+0039, U+0041 to U+005A, U+005F, U+0061 to U+007A
Replace the character with a string formed as follows:
1.
Let s be an empty string.
2.
For each byte b of the character when expressed in the selected character
encoding in turn, run the appropriate subsubsubstep from the list below:
↪ If the byte is in the range 0x20, 0x2A, 0x2D, 0x2E, 0x30 to
0x39, 0x41 to 0x5A, 0x5F, 0x61 to 0x7A
Append to s the Unicode character with the codepoint equal to
the byte.
↪ Otherwise
Append to the string a U+0025 PERCENT SIGN character (%)
followed by two characters in the ranges U+0030 DIGIT ZERO (0)
to U+0039 DIGIT NINE (9) and U+0041 LATIN CAPITAL LETTER A
to U+0046 LATIN CAPITAL LETTER F representing the
hexadecimal value of the byte (zero-padded if necessary).
↪ Otherwise
Leave the character as is.
5.
If the entry's name is "isindex", its type is "text", and this is the first entry in the form data
set, then append the value to result and skip the rest of the substeps for this entry, moving on
to the next entry, if any, or the next step in the overall algorithm otherwise.
6.
If this is not the first entry, append a single U+0026 AMPERSAND character (&) to result.
7.
Append the entry's name to result.
365
5.
8.
Append a single U+003D EQUALS SIGN character (=) to result.
9.
Append the entry's value to result.
Encode result as US-ASCII and return the resulting byte stream.
4.10.21.5 Multipart form data
The multipart/form-data encoding algorithm is to encode the form data set using the rules described by
RFC2388, Returning Values from Forms: multipart/form-data, and return the resulting byte stream.
[RFC2388] p703
Each entry in the form data set is a field, the name of the entry is the field name and the value of the entry is the
field value, unless the entry's name is "_charset_" and its type is "hidden", in which case the field value is the
character encoding used by the aforementioned algorithm to encode the value of the field.
The order of parts must be the same as the order of fields in the form data set. Multiple entries with the same
name must be treated as distinct fields.
4.10.21.6 Plain text form data
The text/plain encoding algorithm is as follows:
1.
Let result be the empty string.
2.
If the form p297 element has an accept-charset p298 attribute, then, taking into account the characters
found in the form data set's names and values, and the character encodings supported by the user
agent, select a character encoding from the list given in the form p297 's accept-charset p298 attribute. If
none of the encodings are supported, then let the selected character encoding be UTF-8.
Otherwise, the selected character encoding is the document's character encoding p75 .
3.
Let charset be the preferred MIME name p28 of the selected character encoding.
4.
If the entry's name is "_charset_" and its type is "hidden", replace its value with charset.
5.
If the entry's type is "file", replace its value with the file's filename only.
6.
For each entry in the form data set, perform these substeps:
7.
1.
Append the entry's name to result.
2.
Append a single U+003D EQUALS SIGN character (=) to result.
3.
Append the entry's value to result.
4.
Append a U+000D CARRIAGE RETURN (CR) U+000A LINE FEED (LF) character pair to result.
Encode result using the selected character encoding and return the resulting byte stream.
4.10.22 Resetting a form
When a form form is reset, the user agent must fire a simple event p496 named reset, that is cancelable, at form,
and then, if that event is not canceled, must invoke the reset algorithm p366 of each resettable elements p297 whose
form owner p353 is form, and broadcast formchange events p366 from form.
Each resettable element p297 defines its own reset algorithm. Changes made to form controls as part of these
algorithms do not count as changes caused by the user (and thus, e.g., do not cause input events to fire).
4.10.23 Event dispatch
When the user agent is to broadcast forminput events or broadcast formchange events from a form p297
element form, it must run the following steps:
366
1.
Let controls be a list of all the resettable elements p297 whose form owner p353 is form.
2.
If the user agent was to broadcast forminput events p366 , let event name be forminput. Otherwise the
user agent was to broadcast formchange events p366 ; let event name be formchange.
3.
For each element in controls, in tree order p27 , fire a simple event p496 named event name at the element.
4.11 Interactive elements
4.11.1 The details element
Categories
Flow content p91 .
Sectioning root p144 .
Interactive content p92 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
One summary p370 element followed by flow content p91 .
Content attributes:
Global attributes p82
open p367
DOM interface:
interface HTMLDetailsElement : HTMLElement {
attribute boolean open;
};
The details p367 element represents p638 a disclosure widget from which the user can obtain additional information
or controls.
Note: The details p367 element is not appropriate for footnotes. Please see the section on
footnotes p395 for details on how to mark up footnotes.
The first summary p370 element child of the element, if any, represents p638 the summary or legend of the details. If
there is no child summary p370 element, the user agent should provide its own legend (e.g. "Details").
The open content attribute is a boolean attribute p34 . If present, it indicates that the details are to be shown to the
user. If the attribute is absent, the details are not to be shown.
If the attribute is removed, then the details should be hidden. If the attribute is added, the details should be
shown.
The user agent should allow the user to request that the details be shown or hidden. To honor a request for the
details to be shown, the user agent must set the open p367 attribute on the element to the value open. To honor a
request for the details to be hidden, the user agent must remove the open p367 attribute from the element.
The open attribute must reflect p57 the open p367 content attribute.
The following example shows the details p367 element being used to hide technical details in a progress
report.
Copying "Really Achieving Your Childhood Dreams"
Copying...
Transfer rate: 452KB/s
Local filename: /home/rpausch/raycd.m4v
Remote filename: /var/www/lectures/raycd.m4v
Duration: 01:16:27
Color profile: SD (6-1-6)
Dimensions: 320×240
The following shows how a details p367 element can be used to hide some controls by default:
Name & Extension:
367
One could use this in conjuction with other details p367 in a list to allow the user to collapse a set of fields
down to a small set of headings, with the ability to open each one.
368
369
In these examples, the summary really just summarises what the controls can change, and not the actual
values, which is less than ideal.
4.11.2 The summary element
Categories
None.
Contexts in which this element may be used:
As the first child of a details p367 element.
Content model:
Phrasing content p91 .
Content attributes:
Global attributes p82
DOM interface:
Uses HTMLElement p81 .
The summary p370 element represents p638 a summary, caption, or legend for the rest of the contents of the
summary p370 element's parent details p367 element, if any.
370
4.11.3 The command element
Categories
Metadata content p90 .
Flow content p91 .
Phrasing content p91 .
Contexts in which this element may be used:
Where metadata content p90 is expected.
Where phrasing content p91 is expected.
Content model:
Empty.
Content attributes:
Global attributes p82
type p371
label p371
icon p371
disabled p371
checked p372
radiogroup p372
Also, the title p371 attribute has special semantics on this element.
DOM interface:
interface HTMLCommandElement : HTMLElement {
attribute DOMString type;
attribute DOMString label;
attribute DOMString icon;
attribute boolean disabled;
attribute boolean checked;
attribute DOMString radiogroup;
};
The command p371 element represents a command that the user can invoke.
The type attribute indicates the kind of command: either a normal command with an associated action, or a state
or option that can be toggled, or a selection of one item from a list of items.
The attribute is an enumerated attribute p34 with three keywords and states. The "command" keyword maps to the
Command p371 state, the "checkbox" keyword maps to the Checkbox p371 state, and the "radio" keyword maps to
the Radio p371 state. The missing value default is the Command p371 state.
The Command state
The element represents p638 a normal command with an associated action.
The Checkbox state
The element represents p638 a state or option that can be toggled.
The Radio state
The element represents p638 a selection of one item from a list of items.
The label attribute gives the name of the command, as shown to the user. The label p371 attribute must be
specified and must have a value that is not the empty string.
The title attribute gives a hint describing the command, which might be shown to the user to help him.
The icon attribute gives a picture that represents the command. If the attribute is specified, the attribute's value
must contain a valid non-empty URL p51 . To obtain the absolute URL p52 of the icon when the attribute's value is not
the empty string, the attribute's value must be resolved p51 relative to the element. When the attribute is absent,
or its value is the empty string, or resolving p51 its value fails, there is no icon.
The disabled attribute is a boolean attribute p34 that, if present, indicates that the command is not available in the
current state.
Note: The distinction between disabled p371 and hidden p508 is subtle. A command would be
disabled if, in the same context, it could be enabled if only certain aspects of the situation
were changed. A command would be marked as hidden if, in that situation, the command will
never be enabled. For example, in the context menu for a water faucet, the command "open"
371
might be disabled if the faucet is already open, but the command "eat" would be marked
hidden since the faucet could never be eaten.
The checked attribute is a boolean attribute p34 that, if present, indicates that the command is selected. The
attribute must be omitted unless the type p371 attribute is in either the Checkbox p371 state or the Radio p371 state.
The radiogroup attribute gives the name of the group of commands that will be toggled when the command itself
is toggled, for commands whose type p371 attribute has the value "radio". The scope of the name is the child list of
the parent element. The attribute must be omitted unless the type p371 attribute is in the Radio p371 state.
The type, label, icon, disabled, checked, and radiogroup IDL attributes must reflect p57 the respective content
attributes of the same name.
The element's activation behavior p93 depends on the value of the type p371 attribute of the element, as follows:
p371
attribute is in the Checkbox p371 state
↪ If the type
If the element has a checked p372 attribute, the UA must remove that attribute. Otherwise, the UA must
add a checked p372 attribute, with the literal value checked. The UA must then fire a click event p496 at
the element.
p371
attribute is in the Radio p371 state
↪ If the type
If the element has a parent, then the UA must walk the list of child nodes of that parent element, and for
each node that is a command p371 element, if that element has a radiogroup p372 attribute whose value
exactly matches the current element's (treating missing radiogroup p372 attributes as if they were the
empty string), and has a checked p372 attribute, must remove that attribute.
Then, the element's checked p372 attribute attribute must be set to the literal value checked and the user
agent must fire a click event p496 at the element.
↪ Otherwise
The element has no activation behavior p93 .
Note: Firing a synthetic click p31 event at the element does not cause any of the actions
described above to happen.
Note: command p371 elements are not rendered unless they form part of a menu p372 .
Here is an example of a toolbar with three buttons that let the user toggle between left, center, and right
alignment. One could imagine such a toolbar as part of a text editor. The toolbar also has a separator
followed by another button labeled "Publish", though that button is disabled.
4.11.4 The menu element
Categories
Flow content p91 .
If the element's type p373 attribute is in the toolbar p373 state: Interactive content p92 .
Contexts in which this element may be used:
Where flow content p91 is expected.
Content model:
Either: Zero or more li p154 elements.
Or: Flow content p91 .
Content attributes:
Global attributes p82
type p373
372
label p373
DOM interface:
interface HTMLMenuElement : HTMLElement {
attribute DOMString type;
attribute DOMString label;
};
The menu p372 element represents a list of commands.
The type attribute is an enumerated attribute p34 indicating the kind of menu being declared. The attribute has
three states. The context keyword maps to the context menu state, in which the element is declaring a context
menu. The toolbar keyword maps to the toolbar state, in which the element is declaring a toolbar. The attribute
may also be omitted. The missing value default is the list state, which indicates that the element is merely a list
of commands that is neither declaring a context menu nor defining a toolbar.
If a menu p372 element's type p373 attribute is in the context menu p373 state, then the element represents p638 the
commands of a context menu, and the user can only interact with the commands if that context menu is
activated.
If a menu p372 element's type p373 attribute is in the toolbar p373 state, then the element represents p638 a list of active
commands that the user can immediately interact with.
If a menu p372 element's type p373 attribute is in the list p373 state, then the element either represents p638 an unordered
list of items (each represented by an li p154 element), each of which represents a command that the user can
perform or activate, or, if the element has no li p154 element children, flow content p91 describing available
commands.
The label attribute gives the label of the menu. It is used by user agents to display nested menus in the UI. For
example, a context menu containing another menu would use the nested menu's label p373 attribute for the
submenu's menu label.
The type and label IDL attributes must reflect p57 the respective content attributes of the same name.
4.11.4.1 Introduction
This section is non-normative.
The menu p372 element is used to define context menus and toolbars.
For example, the following represents a toolbar with three menu buttons on it, each of which has a dropdown
menu with a series of options:
New...
Open...
Save
Save as...
Copy
Cut
Paste
Help About
In a supporting user agent, this might look like this:
373
In a legacy user agent, the above would look like a bulleted list with three items, the first of which has four
buttons, the second of which has three, and the third of which has two nested bullet points with two items
consisting of links.
The following implements a similar toolbar, with a single button whose values, when selected, redirect the user to
Web sites.
The behavior in supporting user agents is similar to the example above, but here the legacy behavior consists of a
single select p334 element with a submit button. The submit button doesn't appear in the toolbar, because it is not
a direct child of the menu p372 element or of its li p154 children.
4.11.4.2 Building menus and toolbars
A menu (or toolbar) consists of a list of zero or more of the following components:
•
•
•
Commands p376 , which can be marked as default commands
Separators
Other menus (which allows the list to be nested)
The list corresponding to a particular menu p372 element is built by iterating over its child nodes. For each child node
in tree order p27 , the required behavior depends on what the node is, as follows:
p376
↪ An element that defines a command
Append the command to the menu, respecting its facets p376 .
p149
element
↪ An hr
p339
element that has a value p340 attribute set to the empty string, and has a disabled p340
↪ An option
attribute, and whose textContent p31 consists of a string of one or more hyphens (U+002D HYPHENMINUS)
Append a separator to the menu.
p154
element
↪ An li
p301
element
↪ A label
Iterate over the children of the element.
p372
element with no label p373 attribute
↪ A menu
p334
element
↪ A select
Append a separator to the menu, then iterate over the children of the menu p372 or select p334 element,
then append another separator.
p372
element with a label p373 attribute
↪ A menu
p338
element with a label p373 attribute
↪ An optgroup
Append a submenu to the menu, using the value of the element's label attribute as the label of the
menu. The submenu must be constructed by taking the element and creating a new menu for it using
the complete process described in this section.
↪ Any other node
Ignore p27 the node.
374
Once all the nodes have been processed as described above, the user agent must the post-process the menu as
follows:
1.
Except for separators, any menu item with no label, or whose label is the empty string, must be
removed.
2.
Any sequence of two or more separators in a row must be collapsed to a single separator.
3.
Any separator at the start or end of the menu must be removed.
4.11.4.3 Context menus
The contextmenu attribute gives the element's context menu p375 . The value must be the ID of a menu p372 element
in the DOM. If the node that would be obtained by the invoking the getElementById() p31 method using the
attribute's value as the only argument is null or not a menu p372 element, then the element has no assigned context
menu. Otherwise, the element's assigned context menu is the element so identified.
When an element's context menu is requested (e.g. by the user right-clicking the element, or pressing a context
menu key), the UA must fire a simple event p496 named contextmenu that bubbles and is cancelable at the element
for which the menu was requested.
Note: Typically, therefore, the firing of the contextmenu event will be the default action of a
mouseup or keyup event. The exact sequence of events is UA-dependent, as it will vary based on
platform conventions.
The default action of the contextmenu event depends on whether the element or one of its ancestors has a
context menu assigned (using the contextmenu p375 attribute) or not. If there is no context menu assigned, the
default action must be for the user agent to show its default context menu, if it has one.
If the element or one of its ancestors does have a context menu assigned, then the user agent must fire a simple
event p496 named show at the menu p372 element of the context menu of the nearest ancestor (including the element
itself) with one assigned.
The default action of this event is that the user agent must show a context menu built p374 from the menu p372
element.
The user agent may also provide access to its default context menu, if any, with the context menu shown. For
example, it could merge the menu items from the two menus together, or provide the page's context menu as a
submenu of the default menu.
If the user dismisses the menu without making a selection, nothing in particular happens.
If the user selects a menu item that represents a command p376 , then the UA must invoke that command's
Action p376 .
Context menus must not, while being shown, reflect changes in the DOM; they are constructed as the default
action of the show event and must remain as constructed until dismissed.
User agents may provide means for bypassing the context menu processing model, ensuring that the user can
always access the UA's default context menus. For example, the user agent could handle right-clicks that have the
Shift key depressed in such a way that it does not fire the contextmenu event and instead always shows the
default context menu.
The contextMenu attribute must reflect p57 the contextmenu p375 content attribute.
Here is an example of a context menu for an input control:
This adds to items to the control's context menu, one called "Pick random name", and one called "Prefill
other fields based on name". They invoke scripts that are not shown in the example above.
375
4.11.4.4 Toolbars
When a menu p372 element has a type p373 attribute in the toolbar p373 state, then the user agent must build p374 the
menu for that menu p372 element, and use the result in the rendering.
The user agent must reflect changes made to the menu p372 's DOM, by immediately rebuilding p374 the menu.
4.11.5 Commands
A command is the abstraction behind menu items, buttons, and links.
Commands are defined to have the following facets:
Type
The kind of command: "command", meaning it is a normal command; "radio", meaning that triggering the
command will, amongst other things, set the Checked State p376 to true (and probably uncheck some other
commands); or "checkbox", meaning that triggering the command will, amongst other things, toggle the
value of the Checked State p376 .
ID
The name of the command, for referring to the command from the markup or from script. If a command has
no ID, it is an anonymous command.
Label
The name of the command as seen by the user.
Hint
A helpful or descriptive string that can be shown to the user.
Icon
An absolute URL p52 identifying a graphical image that represents the action. A command might not have an
Icon.
Access Key
A key combination selected by the user agent that triggers the command. A command might not have an
Access Key.
Hidden State
Whether the command is hidden or not (basically, whether it should be shown in menus).
Disabled State
Whether the command is relevant and can be triggered or not.
Checked State
Whether the command is checked or not.
Action
The actual effect that triggering the command will have. This could be a scripted event handler, a URL p51 to
which to navigate p459 , or a form submission.
These facets are exposed on elements using the command API:
This box is non-normative. Implementation requirements are given below this box.
element . commandType p377
Exposes the Type p376 facet of the command.
element . id p84
Exposes the ID p376 facet of the command.
element . label p377
Exposes the Label p376 facet of the command.
element . title p84
Exposes the Hint p376 facet of the command.
element . icon p377
Exposes the Icon p376 facet of the command.
376
element . accessKeyLabel p513
Exposes the Access Key p376 facet of the command.
element . hidden p508
Exposes the Hidden State p376 facet of the command.
element . disabled p377
Exposes the Disabled State p376 facet of the command.
element . checked p377
Exposes the Checked State p376 facet of the command.
element . click p508 ()
Triggers the Action p376 of the command.
The commandType attribute must return a string whose value is either "command", "radio", or "checkbox",
depending on whether the Type p376 of the command defined by the element is "command", "radio", or "checkbox"
respectively. If the element does not define a command, it must return null.
The label attribute must return the command's Label p376 , or null if the element does not define a command or
does not specify a Label p376 . This attribute will be shadowed by the label IDL attribute on various elements.
The icon attribute must return the absolute URL p52 of the command's Icon p376 . If the element does not specify an
icon, or if the element does not define a command, then the attribute must return null. This attribute will be
shadowed by the icon p372 IDL attribute on command p371 elements.
The disabled attribute must return true if the command's Disabled State p376 is that the command is disabled, and
false if the command is not disabled. This attribute is not affected by the command's Hidden State p376 . If the
element does not define a command, the attribute must return false. This attribute will be shadowed by the
disabled IDL attribute on various elements.
The checked attribute must return true if the command's Checked State p376 is that the command is checked, and
false if it is that the command is not checked. If the element does not define a command, the attribute must return
false. This attribute will be shadowed by the checked IDL attribute on input p303 and command p371 elements.
Note: The ID p376 facet is exposed by the id p84 IDL attribute, the Hint p376 facet is exposed by the
title p84 IDL attribute, the AccessKey p376 facet is exposed by the accessKeyLabel p513 IDL
attribute, and the Hidden State p376 facet is exposed by the hidden p508 IDL attribute.
This box is non-normative. Implementation requirements are given below this box.
document . commands p377
Returns an HTMLCollection p59 of the elements in the Document p31 that define commands and have
IDs.
The commands attribute of the document's HTMLDocument p71 interface must return an HTMLCollection p59 rooted at
the Document p31 node, whose filter matches only elements that define commands p376 and have IDs p376 .
User agents may expose the commands p376 whose Hidden State p376 facet is false (visible), e.g. in the user agent's
menu bar. User agents are encouraged to do this especially for commands that have Access Keys p376 , as a way to
advertise those keys to the user.
4.11.5.1 Using the a element to define a command
An a p160 element with an href p383 attribute defines a command p376 .
The Type p376 of the command is "command".
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command is the string given by the element's textContent p31 IDL attribute.
377
The Hint p376 of the command is the value of the title p84 attribute of the element. If the attribute is not present,
the Hint p376 is the empty string.
The Icon p376 of the command is the absolute URL p52 obtained from resolving p51 the value of the src p186 attribute of
the first img p186 element descendant of the element, relative to that element, if there is such an element and
resolving its attribute is successful. Otherwise, there is no Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 , if any.
The Hidden State p376 of the command is true (hidden) if the element has a hidden p508 attribute, and false
otherwise.
The Disabled State p376 facet of the command is always false. (The command is always enabled.)
The Checked State p376 of the command is always false. (The command is never checked.)
The Action p376 of the command is to fire a click event p496 at the element.
4.11.5.2 Using the button element to define a command
A button p332 element always defines a command p376 .
The Type p376 , ID p376 , Label p376 , Hint p376 , Icon p376 , Access Key p376 , Hidden State p376 , Checked State p376 , and Action p376
facets of the command are determined as for a elements p377 (see the previous section).
The Disabled State p376 of the command mirrors the disabled p354 state of the button.
4.11.5.3 Using the input element to define a command
An input p303 element whose type p304 attribute is in one of the Submit Button p321 , Reset Button p323 , Image
Button p321 , Button p323 , Radio Button p319 , or Checkbox p318 states defines a command p376 .
The Type p376 of the command is "radio" if the type p304 attribute is in the Radio Button p319 state, "checkbox" if the
type p304 attribute is in the Checkbox p318 state, and "command" otherwise.
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command depends on the Type of the command:
If the Type p376 is "command", then it is the string given by the value p306 attribute, if any, and a UA-dependent,
locale-dependent value that the UA uses to label the button itself if the attribute is absent.
Otherwise, the Type p376 is "radio" or "checkbox". If the element is a labeled control p302 , the textContent p31 of the
first label p301 element in tree order p27 whose labeled control p302 is the element in question is the Label p376 (in DOM
terms, this is the string given by element.labels[0].textContent). Otherwise, the value of the value p306
attribute, if present, is the Label p376 . Otherwise, the Label p376 is the empty string.
The Hint p376 of the command is the value of the title p84 attribute of the input p303 element. If the attribute is not
present, the Hint p376 is the empty string.
If the element's type p304 attribute is in the Image Button p321 state, and the element has a src p186 attribute, and
that attribute's value can be successfully resolved p51 relative to the element, then the Icon p376 of the command is
the absolute URL p52 obtained from resolving that attribute that way. Otherwise, there is no Icon p376 for the
command.
The AccessKey p376 of the command is the element's assigned access key p512 , if any.
The Hidden State p376 of the command is true (hidden) if the element has a hidden p508 attribute, and false
otherwise.
The Disabled State p376 of the command mirrors the disabled p354 state of the control.
The Checked State p376 of the command is true if the command is of Type p376 "radio" or "checkbox" and the element
is checked p354 attribute, and false otherwise.
The Action p376 of the command, if the element has a defined activation behavior p93 , is to run synthetic click
activation steps p92 on the element. Otherwise, it is just to fire a click event p496 at the element.
378
4.11.5.4 Using the option element to define a command
An option p339 element with an ancestor select p334 element and either no value p340 attribute or a value p340
attribute that is not the empty string defines a command p376 .
The Type p376 of the command is "radio" if the option p339 's nearest ancestor select p334 element has no
multiple p335 attribute, and "checkbox" if it does.
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command is the value of the option p339 element's label p340 attribute, if there is one, or the
value of the option p339 element's textContent p31 IDL attribute if there isn't.
The Hint p376 of the command is the string given by the element's title p84 attribute, if any, and the empty string if
the attribute is absent.
There is no Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 , if any.
The Hidden State p376 of the command is true (hidden) if the element has a hidden p508 attribute, and false
otherwise.
The Disabled State p376 of the command is true (disabled) if the element is disabled p340 or if its nearest ancestor
select p334 element is disabled p340 , and false otherwise.
The Checked State p376 of the command is true (checked) if the element's selectedness p340 is true, and false
otherwise.
The Action p376 of the command depends on its Type p376 . If the command is of Type p376 "radio" then it must pick p335
the option p339 element. Otherwise, it must toggle p335 the option p339 element.
4.11.5.5 Using the command element to define a command
A command p371 element defines a command p376 .
The Type p376 of the command is "radio" if the command p371 's type p371 attribute is "radio", "checkbox" if the
attribute's value is "checkbox", and "command" otherwise.
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command is the value of the element's label p371 attribute, if there is one, or the empty string
if it doesn't.
The Hint p376 of the command is the string given by the element's title p371 attribute, if any, and the empty string if
the attribute is absent.
The Icon p376 for the command is the absolute URL p52 obtained from resolving p51 the value of the element's icon p371
attribute, relative to the element, if it has such an attribute and resolving it is successful. Otherwise, there is no
Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 , if any.
The Hidden State p376 of the command is true (hidden) if the element has a hidden p508 attribute, and false
otherwise.
The Disabled State p376 of the command is true (disabled) if the element has a disabled p371 attribute, and false
otherwise.
The Checked State p376 of the command is true (checked) if the element has a checked p372 attribute, and false
otherwise.
The Action p376 of the command, if the element has a defined activation behavior p93 , is to run synthetic click
activation steps p92 on the element. Otherwise, it is just to fire a click event p496 at the element.
4.11.5.6 Using the accesskey attribute on a label element to define a command
A label p301 element that has an assigned access key p512 and a labeled control p302 and whose labeled control p302
defines a command p376 , itself defines a command p376 .
The Type p376 of the command is "command".
379
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command is the string given by the element's textContent p31 IDL attribute.
The Hint p376 of the command is the value of the title p84 attribute of the element.
There is no Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 .
The Hidden State p376 , Disabled State p376 , and Action p376 facets of the command are the same as the respective
facets of the element's labeled control p302 .
The Checked State p376 of the command is always false. (The command is never checked.)
4.11.5.7 Using the accesskey attribute on a legend element to define a command
A legend p301 element that has an assigned access key p512 and is a child of a fieldset p300 element that has a
descendant that is not a descendant of the legend p301 element and is neither a label p301 element nor a legend p301
element but that defines a command p376 , itself defines a command p376 .
The Type p376 of the command is "command".
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command is the string given by the element's textContent p31 IDL attribute.
The Hint p376 of the command is the value of the title p84 attribute of the element.
There is no Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 .
The Hidden State p376 , Disabled State p376 , and Action p376 facets of the command are the same as the respective
facets of the first element in tree order p27 that is a descendant of the parent of the legend p301 element that defines
a command p376 but is not a descendant of the legend p301 element and is neither a label p301 nor a legend p301
element.
The Checked State p376 of the command is always false. (The command is never checked.)
4.11.5.8 Using the accesskey attribute to define a command on other elements
An element that has an assigned access key p512 defines a command p376 .
If one of the other sections that define elements that define commands p376 define that this element defines a
command p376 , then that section applies to this element, and this section does not. Otherwise, this section applies
to that element.
The Type p376 of the command is "command".
The ID p376 of the command is the value of the id p84 attribute of the element, if the attribute is present and not
empty. Otherwise the command is an anonymous command p376 .
The Label p376 of the command depends on the element. If the element is a labeled control p302 , the textContent p31
of the first label p301 element in tree order p27 whose labeled control p302 is the element in question is the Label p376
(in DOM terms, this is the string given by element.labels[0].textContent). Otherwise, the Label p376 is the
textContent p31 of the element itself.
The Hint p376 of the command is the value of the title p84 attribute of the element. If the attribute is not present,
the Hint p376 is the empty string.
There is no Icon p376 for the command.
The AccessKey p376 of the command is the element's assigned access key p512 .
The Hidden State p376 of the command is true (hidden) if the element has a hidden p508 attribute, and false
otherwise.
The Disabled State p376 facet of the command is always false. (The command is always enabled.)
The Checked State p376 of the command is always false. (The command is never checked.)
380
The Action p376 of the command is to run the following steps:
1.
If the element is focusable p510 , run the focusing steps p511 for the element.
2.
If the element has a defined activation behavior p93 , run synthetic click activation steps p92 on the
element.
3.
Otherwise, if the element does not have a defined activation behavior p93 , fire a click event p496 at the
element.
4.11.6 The device element
Categories
Flow content p91 .
Phrasing content p91 .
Interactive content p92 .
Contexts in which this element may be used:
Where phrasing content p91 is expected.
Content model:
Empty.
Content attributes:
Global attributes p82
type p381
DOM interface:
interface HTMLDeviceElement : HTMLElement {
attribute DOMString type;
readonly attribute any data;
};
The device p381 element represents a device selector, to allow the user to give the page access to a device, for
example a video camera.
The type attribute allows the author to specify which kind of device the page would like access to. The attribute is
an enumerated attribute p34 with the keywords given in the first column of the following table, and their
corresponding states given in the cell in second column of the same row.
**
**
RS232 is only included below to give an idea of where we could go with this. Should we instead just make
this only useful for audiovisual streams? Unless there are compelling reasons, we probably should not be
this generic. So far, the reasons aren't that compelling.
Keyword
**
**
State
Device description
Examples
media
Media
Stream of audio and/or video data. A webcam.
fs
File system File system.
A USB-connected media player.
rs232
RS232
A serial port.
RS232 device.
processing model: 'change' event fires once user selects a new device; .data is set to new Stream, LocalFS, or
RS232 object as appropriate.
To start chatting, select a video camera:
element)
videoElement.src = local.remoteStream.URL;
};
};
⚠Warning! To prevent network sniffing from allowing a fourth party to establish a connection to the
PeerToPeerServer p382 using the information sent out-of-band to the PeerToPeerClient p382 and thus
spoofing the client, the configuration information should always be transmitted using an encrypted
connection.
4.12 Links
4.12.1 Hyperlink elements
The a p160 , area p266 , and link p109 elements can, in certain situations described in the definitions of those elements,
represent hyperlinks.
The href attribute on a p160 and area p266 elements must have a value that is a valid URL p51 . This URL p51 is the
destination resource of the hyperlink.
383
Note: The href p383 attribute on a p160 and area p266 elements is not required; when those elements
do not have href p383 attributes they do not represent hyperlinks.
Note: The href p109 attribute on the link p109 element is required (and has to be a valid nonempty URL p51 ), but whether a link p109 element represents a hyperlink or not depends on the
value of the rel p110 attribute of that element.
The target attribute, if present, must be a valid browsing context name or keyword p442 . It gives the name of the
browsing context p439 that will be used. User agents use this name when following hyperlinks p384 .
The ping attribute, if present, gives the URLs of the resources that are interested in being notified if the user
follows the hyperlink. The value must be a set of space-separated tokens p49 , each of which must be a valid nonempty URL p51 . The value is used by the user agent for hyperlink auditing p385 .
For a p160 and area p266 elements that represent hyperlinks, the relationship between the document containing the
hyperlink and the destination resource indicated by the hyperlink is given by the value of the element's rel
attribute, which must be a set of space-separated tokens p49 . The allowed values and their meanings p386 are
defined below. The rel p384 attribute has no default value. If the attribute is omitted or if none of the values in the
attribute are recognized by the user agent, then the document has no particular relationship with the destination
resource other than there being a hyperlink between the two.
The media attribute describes for which media the target document was designed. It is purely advisory. The value
must be a valid media query p51 . The default, if the media p384 attribute is omitted, is "all".
The hreflang attribute on hyperlink elements, if present, gives the language of the linked resource. It is purely
advisory. The value must be a valid BCP 47 language code. [BCP47] p700 User agents must not consider this
attribute authoritative — upon fetching the resource, user agents must use only language information associated
with the resource to determine its language, not metadata included in the link to the resource.
The type attribute, if present, gives the MIME type p26 of the linked resource. It is purely advisory. The value must
be a valid MIME type p26 . User agents must not consider the type p384 attribute authoritative — upon fetching the
resource, user agents must not use metadata included in the link to the resource to determine its type.
4.12.2 Following hyperlinks
When a user follows a hyperlink, the user agent must resolve p51 the URL p51 given by the href p383 attribute of that
hyperlink, relative to the hyperlink element, and if that is successful, must navigate p459 a browsing context p439 to
the resulting absolute URL p52 . In the case of server-side image maps, the URL of the hyperlink must further have
its hyperlink suffix p162 appended to it.
If resolving p51 the URL p51 fails, the user agent may report the error to the user in a user-agent-specific manner,
may navigate to an error page to report the error, or may ignore the error and do nothing.
If the user indicated a specific browsing context p439 when following the hyperlink, or if the user agent is configured
to follow hyperlinks by navigating a particular browsing context, then that must be the browsing context p439 that is
navigated.
Otherwise, if the hyperlink element is an a p160 or area p266 element that has a target p384 attribute, then the
browsing context p439 that is navigated must be chosen by applying the rules for choosing a browsing context given
a browsing context name p442 , using the value of the target p384 attribute as the browsing context name. If these
rules result in the creation of a new browsing context p439 , it must be navigated with replacement enabled p466 .
Otherwise, if the hyperlink element is a sidebar hyperlink p391 and the user agent implements a feature that can be
considered a secondary browsing context, such a secondary browsing context may be selected as the browsing
context to be navigated.
Otherwise, if the hyperlink element is an a p160 or area p266 element with no target p384 attribute, but one of the child
nodes of the head element p76 is a base p108 element with a target p109 attribute, then the browsing context that is
navigated must be chosen by applying the rules for choosing a browsing context given a browsing context
name p442 , using the value of the target p109 attribute of the first such base p108 element as the browsing context
name. If these rules result in the creation of a new browsing context p439 , it must be navigated with replacement
enabled p466 .
Otherwise, the browsing context that must be navigated is the same browsing context as the one which the
hyperlink element itself is in.
The navigation must be done with the browsing context p439 that contains the Document p31 object with which the
hyperlink's element in question is associated as the source browsing context p459 .
384
4.12.2.1 Hyperlink auditing
If an a p160 or area p266 hyperlink element has a ping p384 attribute, and the user follows the hyperlink, and the
hyperlink's URL p51 can be resolved p51 , relative to the hyperlink element, without failure, then the user agent must
take the ping p384 attribute's value, split that string on spaces p49 , resolve p51 each resulting token relative to the
hyperlink element, and then should send a request (as described below) to each of the resulting absolute URLs p52 .
(Tokens that fail to resolve are ignored.) This may be done in parallel with the primary request, and is independent
of the result of that request.
User agents should allow the user to adjust this behavior, for example in conjunction with a setting that disables
the sending of HTTP Referer (sic) headers. Based on the user's preferences, UAs may either ignore p27 the ping p384
attribute altogether, or selectively ignore URLs in the list (e.g. ignoring any third-party URLs).
For URLs that are HTTP URLs, the requests must be performed by fetching p55 the specified URLs using the POST
method, with an entity body with the MIME type p26 text/ping p681 consisting of the four-character string "PING",
from the origin p449 of the Document p31 containing the hyperlink p383 . All relevant cookie and HTTP authentication
headers must be included in the request. Which other headers are required depends on the URLs involved.
p71
of the Document p31 object containing the hyperlink being audited and the
↪ If both the address
ping URL have the same origin p451
The request must include a Ping-From p683 HTTP header with, as its value, the address p71 of the document
containing the hyperlink, and a Ping-To p683 HTTP header with, as its value, the address of the absolute
URL p52 of the target of the hyperlink. The request must not include a Referer (sic) HTTP header.
↪ Otherwise, if the origins are different, but the document containing the hyperlink being audited
was not retrieved over an encrypted connection
The request must include a Referer (sic) HTTP header with, as its value, the current address p71 of the
document containing the hyperlink, a Ping-From p683 HTTP header with the same value, and a Ping-To p683
HTTP header with, as its value, the address of the target of the hyperlink.
↪ Otherwise, the origins are different and the document containing the hyperlink being audited was
retrieved over an encrypted connection
The request must include a Ping-To p683 HTTP header with, as its value, the address of the target of the
hyperlink. The request must neither include a Referer (sic) HTTP header nor include a Ping-From p683
HTTP header.
Note: To save bandwidth, implementors might also wish to consider omitting optional headers
such as Accept from these requests.
User agents must, unless otherwise specified by the user, honor the HTTP headers (including, in particular,
redirects and HTTP cookie headers), but must ignore any entity bodies returned in the responses. User agents may
close the connection prematurely once they start receiving an entity body. [COOKIES] p700
For URLs that are not HTTP URLs, the requests must be performed by fetching p55 the specified URL normally, and
discarding the results.
When the ping p384 attribute is present, user agents should clearly indicate to the user that following the hyperlink
will also cause secondary requests to be sent in the background, possibly including listing the actual target URLs.
For example, a visual user agent could include the hostnames of the target ping URLs along with the
hyperlink's actual URL in a status bar or tooltip.
The ping p384 attribute is redundant with pre-existing technologies like HTTP redirects and
JavaScript in allowing Web pages to track which off-site links are most popular or allowing
advertisers to track click-through rates.
However, the ping p384 attribute provides these advantages to the user over those alternatives:
•
It allows the user to see the final target URL unobscured.
•
It allows the UA to inform the user about the out-of-band notifications.
•
It allows the user to disable the notifications without losing the underlying link
functionality.
•
It allows the UA to optimize the use of available network bandwidth so that the target
page loads faster.
Thus, while it is possible to track users without this feature, authors are encouraged to use
the ping p384 attribute so that the user agent can make the user experience more transparent.
385
4.12.3 Link types
The following table summarizes the link types that are defined by this specification. This table is non-normative;
the actual definitions for the link types are given in the next few sections.
In this section, the term referenced document refers to the resource identified by the element representing the
link, and the term current document refers to the resource within which the element representing the link finds
itself.
To determine which link types apply to a link p109 , a p160 , or area p266 element, the element's rel attribute must be
split on spaces p49 . The resulting tokens are the link types that apply to that element.
Except where otherwise specified, a keyword must not be specified more than once per rel attribute.
The link types that contain no U+003A COLON characters (:), including all those defined in this specification, are
ASCII case-insensitive p33 values, and must be compared as such.
Thus, rel="next" is the same as rel="NEXT".
Link type
Effect on...
link p109
Brief description
a p160 and
area p266
alternate p386
Hyperlink p110
Hyperlink p383 Gives alternate representations of the current document.
archives p387
Hyperlink p110
Hyperlink p383 Provides a link to a collection of records, documents, or other materials of historical
interest.
author p387
Hyperlink p110
Hyperlink p383 Gives a link to the current document's author.
bookmark
p388
not allowed
Hyperlink p383 Gives the permalink for the nearest ancestor section.
external
p388
not allowed
Hyperlink p383 Indicates that the referenced document is not part of the same site as the current
document.
first p393
Hyperlink p110
Hyperlink p383 Indicates that the current document is a part of a series, and that the first document in
the series is the referenced document.
help p388
Hyperlink p110
Hyperlink p383 Provides a link to context-sensitive help.
External
Resource p110
not allowed
index p392
Hyperlink p110
Hyperlink p383 Gives a link to the document that provides a table of contents or index listing the current
document.
last p393
Hyperlink p110
Hyperlink p383 Indicates that the current document is a part of a series, and that the last document in the
series is the referenced document.
license p390
Hyperlink p110
Hyperlink p383 Indicates that the main content of the current document is covered by the copyright
license described by the referenced document.
next p393
Hyperlink p110
Hyperlink p383 Indicates that the current document is a part of a series, and that the next document in
the series is the referenced document.
nofollow p390
not allowed
Hyperlink p383 Indicates that the current document's original author or publisher does not endorse the
referenced document.
icon
p389
Imports an icon to represent the current document.
noreferrer p390 not allowed
Hyperlink p383 Requires that the user agent not send an HTTP Referer (sic) header if the user follows the
hyperlink.
pingback p390
External
Resource p110
not allowed
Gives the address of the pingback server that handles pingbacks to the current document.
prefetch p391
External
Resource p110
not allowed
Specifies that the target resource should be preemptively cached.
prev p393
Hyperlink p110
Hyperlink p383 Indicates that the current document is a part of a series, and that the previous document
in the series is the referenced document.
search p391
Hyperlink p110
Hyperlink p383 Gives a link to a resource that can be used to search through the current document and its
related pages.
stylesheet p391 External
Resource p110
not allowed
sidebar p391
Hyperlink p110
Hyperlink p383 Specifies that the referenced document, if retrieved, is intended to be shown in the
browser's sidebar (if it has one).
tag p391
Hyperlink p110
Hyperlink p383 Gives a tag (identified by the given address) that applies to the current document.
up p392
Hyperlink p110
Hyperlink p383 Provides a link to a document giving the context for the current document.
Imports a stylesheet.
Some of the types described below list synonyms for these values. These are to be handled as specified by user
agents, but must not be used in documents.
4.12.3.1 Link type "alternate"
The alternate p386 keyword may be used with link p109 , a p160 , and area p266 elements.
The meaning of this keyword depends on the values of the other attributes.
386
p109
element and the rel p110 attribute also contains the keyword
↪ If the element is a link
p391
stylesheet
The alternate p386 keyword modifies the meaning of the stylesheet p391 keyword in the way described
for that keyword. The alternate p386 keyword does not create a link of its own.
p386
keyword is used with the type p384 attribute set to the value application/rss+xml
↪ The alternate
or the value application/atom+xml
The link is a hyperlink p110 referencing a syndication feed (though not necessarily syndicating exactly the
same content as the current page).
The first link p109 , a p160 , or area p266 element in the document (in tree order) with the alternate p386
keyword used with the type p384 attribute set to the value application/rss+xml or the value
application/atom+xml must be treated as the default syndication feed for the purposes of feed
autodiscovery.
The following link p109 element gives the syndication feed for the current page:
You can access the planets database using Atom feeds:
↪ Otherwise
The link is a hyperlink p110 referencing an alternate representation of the current document.
The nature of the referenced document is given by the media p384 , hreflang p384 , and type p384 attributes.
If the alternate p386 keyword is used with the media p384 attribute, it indicates that the referenced
document is intended for use with the media specified.
If the alternate p386 keyword is used with the hreflang p384 attribute, and that attribute's value differs
from the root element p27 's language p85 , it indicates that the referenced document is a translation.
If the alternate p386 keyword is used with the type p384 attribute, it indicates that the referenced
document is a reformulation of the current document in the specified format.
The media p384 , hreflang p384 , and type p384 attributes can be combined when specified with the
alternate p386 keyword.
For example, the following link is a French translation that uses the PDF format:
Example of permalinks
First example
This permalink applies to
only the content from the first H2 to the second H2. The DIV isn't
exactly that section, but it roughly corresponds to it.
Second example
This permalink applies to
the outer ARTICLE element (which could be, e.g., a blog post).
This permalink applies to
the inner ARTICLE element (which could be, e.g., a blog comment).
...
4.12.3.5 Link type "external"
The external p388 keyword may be used with a p160 and area p266 elements.
The external p388 keyword indicates that the link is leading to a document that is not part of the site that the
current document forms a part of.
4.12.3.6 Link type "help"
The help p388 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
For a p160 and area p266 elements, the help p388 keyword indicates that the referenced document provides further
help information for the parent of the element defining the hyperlink, and its children.
In the following example, the form control has associated context-sensitive help. The user agent could use
this information, for example, displaying the referenced document if the user presses the "Help" or "F1" key.
Topic: (Help)
For link p109 elements, the help p388 keyword indicates that the referenced document provides help for the page as
a whole.
388
4.12.3.7 Link type "icon"
The icon p389 keyword may be used with link p109 elements, for which it creates an external resource link p110 .
The specified resource is an icon representing the page or site, and should be used by the user agent when
representing the page in the user interface.
Icons could be auditory icons, visual icons, or other kinds of icons. If multiple icons are provided, the user agent
must select the most appropriate icon according to the type p111 , media p111 , and sizes p389 attributes. If there are
multiple equally appropriate icons, user agents must use the last one declared in tree order p27 . If the user agent
tries to use an icon but that icon is determined, upon closer examination, to in fact be inappropriate (e.g. because
it uses an unsupported format), then the user agent must try the next-most-appropriate icon as determined by the
attributes.
There is no default type for resources given by the icon p389 keyword. However, for the purposes of determining the
type of the resource p111 , user agents must expect the resource to be an image.
The sizes attribute gives the sizes of icons for visual media.
If specified, the attribute must have a value that is an unordered set of unique space-separated tokens p49 . The
values must all be either any p389 or a value that consists of two valid non-negative integers p35 that do not have a
leading U+0030 DIGIT ZERO (0) character and that are separated by a single U+0078 LATIN SMALL LETTER X
character (x).
The keywords represent icon sizes.
To parse and process the attribute's value, the user agent must first split the attribute's value on spaces p49 , and
must then parse each resulting keyword to determine what it represents.
The any keyword represents that the resource contains a scalable icon, e.g. as provided by an SVG image.
Other keywords must be further parsed as follows to determine what they represent:
•
If the keyword doesn't contain exactly one U+0078 LATIN SMALL LETTER X character (x), then this
keyword doesn't represent anything. Abort these steps for that keyword.
•
Let width string be the string before the "x".
•
Let height string be the string after the "x".
•
If either width string or height string start with a U+0030 DIGIT ZERO (0) character or contain any
characters other than characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then
this keyword doesn't represent anything. Abort these steps for that keyword.
•
Apply the rules for parsing non-negative integers p35 to width string to obtain width.
•
Apply the rules for parsing non-negative integers p35 to height string to obtain height.
•
The keyword represents that the resource contains a bitmap icon with a width of width device pixels and
a height of height device pixels.
The keywords specified on the sizes p389 attribute must not represent icon sizes that are not actually available in
the linked resource.
If the attribute is not specified, then the user agent must assume that the given icon is appropriate, but less
appropriate than an icon of a known and appropriate size.
The following snippet shows the top part of an application with several icons.
lsForums — Inbox
Exampl Pictures: Kissat
Kissat
Return to photo index
Kissat
One of them has six toes!
MIT Licensed
In this case the license p390 applies to just the photo (the main content of the document), not the whole
document. In particular not the design of the page itself, which is covered by the copyright given at the
bottom of the document. This could be made clearer in the styling (e.g. making the license link prominently
positioned near the photograph, while having the page copyright in light small text at the foot of the page.
Synonyms: For historical reasons, user agents must also treat the keyword "copyright" like the license p390
keyword.
4.12.3.9 Link type "nofollow"
The nofollow p390 keyword may be used with a p160 and area p266 elements.
The nofollow p390 keyword indicates that the link is not endorsed by the original author or publisher of the page, or
that the link to the referenced document was included primarily because of a commercial relationship between
people affiliated with the two pages.
4.12.3.10 Link type "noreferrer"
The noreferrer p390 keyword may be used with a p160 and area p266 elements.
It indicates that no referrer information is to be leaked when following the link.
If a user agent follows a link defined by an a p160 or area p266 element that has the noreferrer p390 keyword, the user
agent must not include a Referer (sic) HTTP header (or equivalent p56 for other protocols) in the request.
This keyword also causes the opener attribute to remain null p442 if the hyperlink creates a new browsing
context p439 .
4.12.3.11 Link type "pingback"
The pingback p390 keyword may be used with link p109 elements, for which it creates an external resource link p110 .
390
For the semantics of the pingback p390 keyword, see the Pingback 1.0 specification. [PINGBACK] p702
4.12.3.12 Link type "prefetch"
The prefetch p391 keyword may be used with link p109 elements, for which it creates an external resource link p110 .
The prefetch p391 keyword indicates that preemptively fetching and caching the specified resource is likely to be
beneficial, as it is highly likely that the user will require this resource.
There is no default type for resources given by the prefetch p391 keyword.
4.12.3.13 Link type "search"
The search p391 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates
a hyperlink p110 .
The search p391 keyword indicates that the referenced document provides an interface specifically for searching the
document and its related resources.
Note: OpenSearch description documents can be used with link p109 elements and the search p391
link type to enable user agents to autodiscover search interfaces. [OPENSEARCH] p702
4.12.3.14 Link type "stylesheet"
The stylesheet p391 keyword may be used with link p109 elements, for which it creates an external resource link p110
that contributes to the styling processing model p121 .
The specified resource is a resource that describes how to present the document. Exactly how the resource is to
be processed depends on the actual type of the resource.
If the alternate p386 keyword is also specified on the link p109 element, then the link is an alternative
stylesheet; in this case, the title p84 attribute must be specified on the link p109 element, with a non-empty
value.
The default type for resources given by the stylesheet p391 keyword is text/css.
Quirk: If the document has been set to quirks mode p75 and the Content-Type metadata p57 of the external resource
is not a supported style sheet type, the user agent must instead assume it to be text/css.
4.12.3.15 Link type "sidebar"
The sidebar p391 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates
a hyperlink p110 .
The sidebar p391 keyword indicates that the referenced document, if retrieved, is intended to be shown in a
secondary browsing context p441 (if possible), instead of in the current browsing context p439 .
A hyperlink element p383 with the sidebar p391 keyword specified is a sidebar hyperlink.
4.12.3.16 Link type "tag"
The tag p391 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The tag p391 keyword indicates that the tag that the referenced document represents applies to the current
document.
Note: Since it indicates that the tag applies to the current document, it would be
inappropriate to use this keyword in the markup of a tag cloud p394 , which lists the popular tag
across a set of pages.
4.12.3.17 Hierarchical link types
Some documents form part of a hierarchical structure of documents.
A hierarchical structure of documents is one where each document can have various subdocuments. The
document of which a document is a subdocument is said to be the document's parent. A document with no parent
forms the top of the hierarchy.
391
A document may be part of multiple hierarchies.
4.12.3.17.1 Link type "index"
The index p392 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The index p392 keyword indicates that the document is part of a hierarchical structure, and that the link is leading
to the document that is the top of the hierarchy. It conveys more information when used with the up p392 keyword
(q.v.).
Synonyms: For historical reasons, user agents must also treat the keywords "top", "contents", and "toc" like the
index p392 keyword.
4.12.3.17.2 Link type "up"
The up p392 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The up p392 keyword indicates that the document is part of a hierarchical structure, and that the link is leading to a
document that is an ancestor of the current document.
The up p392 keyword may be repeated within a rel p384 attribute to indicate the hierarchical distance from the
current document to the referenced document. If it occurs only once, then the link is leading to the current
document's parent; each additional occurrence of the keyword represents one further level. If the index p392
keyword is also present, then the number of up p392 keywords is the depth of the current page relative to the top of
the hierarchy. Only one link is created for the set of one or more up p392 keywords and, if present, the index p392
keyword.
If the page is part of multiple hierarchies, then they should be described in different paragraphs p93 . User agents
must scope any interpretation of the up p392 and index p392 keywords together indicating the depth of the hierarchy
to the paragraph p93 in which the link finds itself, if any, or to the document otherwise.
When two links have both the up p392 and index p392 keywords specified together in the same scope and contradict
each other by having a different number of up p392 keywords, the link with the greater number of up p392 keywords
must be taken as giving the depth of the document.
This can be used to mark up a navigation style sometimes known as bread crumbs. In the following
example, the current page can be reached via two paths.
Main >
Products >
Dishwashers >
Second hand
Main >
Second hand >
Dishwashers
Note: The relList p162 IDL attribute (e.g. on the a p160 element) does not currently represent
multiple up p392 keywords (the interface hides duplicates).
4.12.3.18 Sequential link types
Some documents form part of a sequence of documents.
A sequence of documents is one where each document can have a previous sibling and a next sibling. A document
with no previous sibling is the start of its sequence, a document with no next sibling is the end of its sequence.
A document may be part of multiple sequences.
392
4.12.3.18.1 Link type "first"
The first p393 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The first p393 keyword indicates that the document is part of a sequence, and that the link is leading to the
document that is the first logical document in the sequence.
Synonyms: For historical reasons, user agents must also treat the keywords "begin" and "start" like the
first p393 keyword.
4.12.3.18.2 Link type "last"
The last p393 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The last p393 keyword indicates that the document is part of a sequence, and that the link is leading to the
document that is the last logical document in the sequence.
Synonyms: For historical reasons, user agents must also treat the keyword "end" like the last p393 keyword.
4.12.3.18.3 Link type "next"
The next p393 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The next p393 keyword indicates that the document is part of a sequence, and that the link is leading to the
document that is the next logical document in the sequence.
4.12.3.18.4 Link type "prev"
The prev p393 keyword may be used with link p109 , a p160 , and area p266 elements. For link p109 elements, it creates a
hyperlink p110 .
The prev p393 keyword indicates that the document is part of a sequence, and that the link is leading to the
document that is the previous logical document in the sequence.
Synonyms: For historical reasons, user agents must also treat the keyword "previous" like the prev p393 keyword.
4.12.3.19 Other link types
Extensions to the predefined set of link types may be registered in the WHATWG Wiki RelExtensions page.
[WHATWGWIKI] p704
Anyone is free to edit the WHATWG Wiki RelExtensions page at any time to add a type. Extension types must be
specified with the following information:
Keyword
The actual value being defined. The value should not be confusingly similar to any other defined value (e.g.
differing only in case).
If the value contains a U+003A COLON character (:), it must also be an absolute URL p52 .
Effect on... link p109
One of the following:
not allowed
The keyword is not allowed to be specified on link p109 elements.
Hyperlink
The keyword may be specified on a link p109 element; it creates a hyperlink link p110 .
External Resource
The keyword may be specified on a link p109 element; it creates a external resource link p110 .
Effect on... a p160 and area p266
One of the following:
not allowed
The keyword is not allowed to be specified on a p160 and area p266 elements.
Hyperlink
The keyword may be specified on a p160 and area p266 elements.
393
Brief description
A short non-normative description of what the keyword's meaning is.
Specification
A link to a more detailed description of the keyword's semantics and requirements. It could be another page
on the Wiki, or a link to an external page.
Synonyms
A list of other keyword values that have exactly the same processing requirements. Authors should not use
the values defined to be synonyms, they are only intended to allow user agents to support legacy content.
Anyone may remove synonyms that are not used in practice; only names that need to be processed as
synonyms for compatibility with legacy content are to be registered in this way.
Status
One of the following:
Proposed
The keyword has not received wide peer review and approval. Someone has proposed it and is, or soon
will be, using it.
Ratified
The keyword has received wide peer review and approval. It has a specification that unambiguously
defines how to handle pages that use the keyword, including when they use it in incorrect ways.
Discontinued
The keyword has received wide peer review and it has been found wanting. Existing pages are using
this keyword, but new pages should avoid it. The "brief description" and "specification" entries will give
details of what authors should use instead, if anything.
If a keyword is found to be redundant with existing values, it should be removed and listed as a synonym for
the existing value.
If a keyword is registered in the "proposed" state for a period of a month or more without being used or
specified, then it may be removed from the registry.
If a keyword is added with the "proposed" status and found to be redundant with existing values, it should be
removed and listed as a synonym for the existing value. If a keyword is added with the "proposed" status
and found to be harmful, then it should be changed to "discontinued" status.
Anyone can change the status at any time, but should only do so in accordance with the definitions above.
Conformance checkers must use the information given on the WHATWG Wiki RelExtensions page to establish if a
value is allowed or not: values defined in this specification or marked as "proposed" or "ratified" must be accepted
when used on the elements for which they apply as described in the "Effect on..." field, whereas values marked as
"discontinued" or not listed in either this specification or on the aforementioned page must be rejected as invalid.
Conformance checkers may cache this information (e.g. for performance reasons or to avoid the use of unreliable
network connectivity).
When an author uses a new type not defined by either this specification or the Wiki page, conformance checkers
should offer to add the value to the Wiki, with the details described above, with the "proposed" status.
Types defined as extensions in the WHATWG Wiki RelExtensions page with the status "proposed" or "ratified" may
be used with the rel attribute on link p109 , a p160 , and area p266 elements in accordance to the "Effect on..." field.
[WHATWGWIKI] p704
4.13 Common idioms without dedicated elements
4.13.1 Tag clouds
This specification does not define any markup specifically for marking up lists of keywords that apply to a group of
pages (also known as tag clouds). In general, authors are encouraged to either mark up such lists using ul p153
elements with explicit inline counts that are then hidden and turned into a presentational effect using a style
sheet, or to use SVG.
Here, three tags are included in a short tag cloud:
...
The actual frequency of each tag is given using the title p84 attribute. A CSS style sheet is provided to
convert the markup into a cloud of differently-sized words, but for user agents that do not support CSS or
are not visual, the markup contains annotations like "(popular)" or "(rare)" to categorize the various tags by
frequency, thus enabling all users to benefit from the information.
The ul p153 element is used (rather than ol p152 ) because the order is not particularly important: while the list
is in fact ordered alphabetically, it would convey the same information if ordered by, say, the length of the
tag.
The tag p391 rel p384 -keyword is not used on these a p160 elements because they do not represent tags that
apply to the page itself; they are just part of an index listing the tags themselves.
4.13.2 Conversations
This specification does not define a specific element for marking up conversations, meeting minutes, chat
transcripts, dialogues in screenplays, instant message logs, and other situations where different players take turns
in discourse.
Instead, authors are encouraged to mark up conversations using p p148 elements and punctuation. Authors who
need to mark the speaker for styling purposes are encouraged to use span p180 or b p175 . Paragraphs with their text
wrapped in the i p174 element can be used for marking up stage directions.
This example demonstrates this using an extract from Abbot and Costello's famous sketch, Who's on first:
Costello: Look, you gotta first baseman?
Abbott: Certainly.
Costello: Who's playing first?
Abbott: That's right.
Costello becomes exasperated.
Costello: When you pay off the first baseman every month, who gets the money?
Abbott: Every dollar of it.
The following extract shows how an IM conversation log could be marked up.
14:22 egof I'm not that nerdy, I've only seen 30% of the star
trek episodes
14:23 kaj if you know what percentage of the star trek
episodes you have seen, you are inarguably nerdy
14:23 egof it's unarguably
14:23 * kaj blinks
14:24 kaj you are not helping your case
4.13.3 Footnotes
HTML does not have a dedicated mechanism for marking up footnotes. Here are the recommended alternatives.
For short inline annotations, the title p84 attribute should be used.
In this example, two parts of a dialogue are annotated with footnote-like content using the title p84
attribute.
Customer : Hello! I wish to register a complaint. Hello. Miss?
Shopkeeper : Watcha mean, miss?
Customer : Uh, I'm sorry, I have a cold. I wish to make a complaint.
Shopkeeper : Sorry, we're
closing for lunch .
395
For longer annotations, the a p160 element should be used, pointing to an element later in the document. The
convention is that the contents of the link be a number in square brackets.
In this example, a footnote in the dialogue links to a paragraph below the dialogue. The paragraph then
reciprocally links back to the dialogue, allowing the user to return to the location of the footnote.
Announcer: Number 16: The hand .
Interviewer: Good evening. I have with me in the studio tonight
Mr Norman St John Polevaulter, who for the past few years has been
contradicting people. Mr Polevaulter, why do you
contradict people?
Norman: I don't. [1]
Interviewer: You told me you did!
...
[1] This is, naturally, a lie,
but paradoxically if it were true he could not say so without
contradicting the interviewer and thus making it false.
For side notes, longer annotations that apply to entire sections of the text rather than just specific words or
sentences, the aside p137 element should be used.
In this example, a sidebar is given after a dialogue, giving it some context.
Customer : I will not buy this record, it is scratched.
Shopkeeper : I'm sorry?
Customer : I will not buy this record, it is scratched.
Shopkeeper : No no no, this's'a tobacconist's.
In 1970, the British Empire lay in ruins, and foreign
nationalists frequented the streets — many of them Hungarians
(not the streets — the foreign nationals). Sadly, Alexander
Yalt has been publishing incompetently-written phrase books.
For figures or tables, footnotes can be included in the relevant figcaption p159 or caption p277 element, or in
surrounding prose.
In this example, a table has cells with footnotes that are given in prose. A figure p158 element is used to give
a single legend to the combination of the table and its footnotes.
Table 1. Alternative activities for knights.
Activity
Location
Cost
Dance
Wherever possible
£01
Routines, chorus scenes2 Undisclosed
Undisclosed
Dining3 Camelot
Cost of ham, jam, and spam4
1. Assumed.
2. Footwork impeccable.
3. Quality described as "well".
4. A lot.
396
4.14 Matching HTML elements using selectors
4.14.1 Case-sensitivity
Attribute and element names of HTML elements p26 in HTML documents p71 must be treated as ASCII caseinsensitive p33 .
Classes from the class p86 attribute of HTML elements p26 in documents that are in quirks mode p75 must be treated
as ASCII case-insensitive p33 .
Attribute selectors on an HTML element p26 in an HTML document p71 must treat the values of attributes with the
following names as ASCII case-insensitive p33 :
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
accept
accept-charset
align
alink
axis
bgcolor
charset
checked
clear
codetype
color
compact
declare
defer
dir
direction
disabled
enctype
face
frame
hreflang
http-equiv
lang
language
link
media
method
multiple
nohref
noresize
noshade
nowrap
readonly
rel
rev
rules
scope
scrolling
selected
shape
target
text
type
valign
valuetype
vlink
All other attribute values on HTML elements p26 must be treated as case-sensitive p33 .
4.14.2 Pseudo-classes
There are a number of dynamic selectors that can be used with HTML. This section defines when these selectors
match HTML elements.
:link
:visited
All a p160 elements that have an href p383 attribute, all area p266 elements that have an href p383 attribute, and
all link p109 elements that have an href p109 attribute, must match one of :link p397 and :visited p397 .
:active
The :active p397 pseudo-class must match the following elements between the time the user begins to
activate the element and the time the user stops activating the element:
•
a p160 elements that have an href p383 attribute
•
area p266 elements that have an href p383 attribute
397
•
link p109 elements that have an href p109 attribute
•
button p332 elements that are not disabled p354
•
input p303 elements whose type p304 attribute is in the Submit Button p321 , Image Button p321 , Reset
Button p323 , or Button p323 state
•
command p371 elements that do not have a disabled p371 attribute
•
any other element, if it is specially focusable p510
For example, if the user is using a keyboard to push a button p332 element by pressing the space bar,
the element would match this pseudo-class in between the time that the element received the
keydown event and the time the element received the keyup event.
:enabled
The :enabled p398 pseudo-class must match the following elements:
•
a p160 elements that have an href p383 attribute
•
area p266 elements that have an href p383 attribute
•
link p109 elements that have an href p109 attribute
•
button p332 elements that are not disabled p354
•
input p303 elements whose type p304 attribute are not in the Hidden p307 state and that are not
disabled p354
•
select p334 elements that are not disabled p354
•
textarea p341 elements that are not disabled p354
•
option p339 elements that do not have a disabled p340 attribute
•
command p371 elements that do not have a disabled p371 attribute
•
li p154 elements that are children of menu p372 elements, and that have a child element that defines a
command p376 , if the first such element's Disabled State p376 facet is false (not disabled)
:disabled
The :disabled p398 pseudo-class must match the following elements:
•
button p332 elements that are disabled p354
•
input p303 elements whose type p304 attribute are not in the Hidden p307 state and that are
disabled p354
•
select p334 elements that are disabled p354
•
textarea p341 elements that are disabled p354
•
option p339 elements that have a disabled p340 attribute
•
command p371 elements that have a disabled p371 attribute
•
li p154 elements that are children of menu p372 elements, and that have a child element that defines a
command p376 , if the first such element's Disabled State p376 facet is true (disabled)
:checked
The :checked p398 pseudo-class must match the following elements:
398
•
input p303 elements whose type p304 attribute is in the Checkbox p318 state and whose
checkedness p354 state is true
•
input p303 elements whose type p304 attribute is in the Radio Button p319 state and whose
checkedness p354 state is true
•
command p371 elements whose type p371 attribute is in the Checkbox p371 state and that have a
checked p372 attribute
•
command p371 elements whose type p371 attribute is in the Radio p371 state and that have a checked p372
attribute
:indeterminate
The :indeterminate p399 pseudo-class must match input p303 elements whose type p304 attribute is in the
Checkbox p318 state and whose indeterminate p307 IDL attribute is set to true.
:default
The :default p399 pseudo-class must match the following elements:
•
button p332 elements that are their form's default button p360
•
input p303 elements whose type p304 attribute is in the Submit Button p321 or Image Button p321 state,
and that are their form's default button p360
:valid
The :valid p399 pseudo-class must match all elements that are candidates for constraint validation p356 and
that satisfy their constraints p357 .
:invalid
The :invalid p399 pseudo-class must match all elements that are candidates for constraint validation p356 but
that do not satisfy their constraints p357 .
:in-range
The :in-range p399 pseudo-class must match all elements that are candidates for constraint validation p356
and that are neither suffering from an underflow p357 nor suffering from an overflow p357 .
:out-of-range
The :out-of-range p399 pseudo-class must match all elements that are candidates for constraint
validation p356 and that are suffering from an underflow p357 or suffering from an overflow p357 .
:required
The :required p399 pseudo-class must match the following elements:
•
input p303 elements that are required p326
•
textarea p341 elements that have a required p343 attribute
:optional
The :optional p399 pseudo-class must match the following elements:
•
button p332 elements
•
input p303 elements that are not required p326
•
select p334 elements
•
textarea p341 elements that do not have a required p343 attribute
:read-only
:read-write
The :read-write p399 pseudo-class must match the following elements:
•
input p303 elements to which the readonly p325 attribute applies, but that are not immutable p306 (i.e.
that do not have the readonly p325 attribute specified and that are not disabled p354 )
•
textarea p341 elements that do not have a readonly p342 attribute, and that are not disabled p354
•
any element that is editable p518
The :read-only p399 pseudo-class must match all other HTML elements p26 .
Note: Another section of this specification defines the target element p465 used with the
:target pseudo-class.
Note: This specification does not define when an element matches the :hover, :focus, or
:lang() dynamic pseudo-classes, as those are all defined in sufficient detail in a languageagnostic fashion in the Selectors specification. [SELECTORS] p703
399
5 Microdata
5.1 Introduction
5.1.1 Overview
This section is non-normative.
Sometimes, it is desirable to annotate content with specific machine-readable labels, e.g. to allow generic scripts
to provide services that are customised to the page, or to enable content from a variety of cooperating authors to
be processed by a single script in a consistent manner.
For this purpose, authors can use the microdata features described in this section. Microdata allows nested groups
of name-value pairs to be added to documents, in parallel with the existing content.
5.1.2 The basic syntax
This section is non-normative.
At a high level, microdata consists of a group of name-value pairs. The groups are called items p405 , and each
name-value pair is a property. Items and properties are represented by regular elements.
To create an item, the itemscope p405 attribute is used.
To add a property to an item, the itemprop p405 attribute is used on one of the item's p405 descendants.
Here there are two items, each of which has the property "name":
Properties generally have values that are strings.
Here the item has three properties:
My name is Neil .
My band is called Four Parts Water .
I am British .
Properties can also have values that are URLs p51 . This is achieved using the a p160 element and its href p383
attribute, the img p186 element and its src p186 attribute, or other elements that link to or embed external resources.
In this example, the item has one property, "image", whose value is a URL:
Properties can also have values that are dates, times, or dates and times. This is achieved using the time p168
element and its datetime p169 attribute.
In this example, the item has one property, "birthday", whose value is a date:
I was born on May 10th 2009 .
Properties can also themselves be groups of name-value pairs, by putting the itemscope p405 attribute on the
element that declares the property.
Items that are not part of others are called top-level microdata items p407 .
In this example, the outer item represents a person, and the inner one represents a band:
Name: Amanda
Band: Jazz Band
400
(12 players)
The outer item here has two properties, "name" and "band". The "name" is "Amanda", and the "band" is an
item in its own right, with two properties, "name" and "size". The "name" of the band is "Jazz Band", and the
"size" is "12".
The outer item in this example is a top-level microdata item.
Properties that are not descendants of the element with the itemscope p405 attribute can be associated with the
item p405 using the itemref p405 attribute. This attribute takes a list of IDs of elements to crawl in addition to
crawling the children of the element with the itemscope p405 attribute.
This example is the same as the previous one, but all the properties are separated from their items p405 :
Name: Amanda
Band: Jazz Band
Size: 12 players
This gives the same result as the previous example. The first item has two properties, "name", set to
"Amanda", and "band", set to another item. That second item has two further properties, "name", set to
"Jazz Band", and "size", set to "12".
An item p405 can have multiple properties with the same name and different values.
This example describes an ice cream, with two flavors:
Flavors in my favorite ice cream:
Lemon sorbet
Apricot sorbet
This thus results in an item with two properties, both "flavor", having the values "Lemon sorbet" and
"Apricot sorbet".
An element introducing a property can also introduce multiple properties at once, to avoid duplication when some
of the properties have the same value.
Here we see an item with two properties, "favorite-color" and "favorite-fruit", both set to the value "orange":
orange
It's important to note that there is no relationship between the microdata and the content of the document where
the microdata is marked up.
There is no semantic difference, for instance, between the following two examples:
The Castle
The Castle (1986)
Both have a figure with a caption, and both, completely unrelated to the figure, have an item with a namevalue pair with the name "name" and the value "The Castle". The only difference is that if the user drags the
caption out of the document, in the former case, the item will be included in the drag-and-drop data. In
neither case is the image in any way associated with the item.
401
5.1.3 Typed items
This section is non-normative.
The examples in the previous section show how information could be marked up on a page that doesn't expect its
microdata to be re-used. Microdata is most useful, though, when it is used in contexts where other authors and
readers are able to cooperate to make new uses of the markup.
For this purpose, it is necessary to give each item p405 a type, such as "http://example.com/person", or
"http://example.org/cat", or "http://band.example.net/". Types are identified as URLs p51 .
The type for an item p405 is given as the value of an itemtype p405 attribute on the same element as the
itemscope p405 attribute.
Here, the item is "http://example.org/animals#cat":
Hedral
Hedral is a male american domestic
shorthair, with a fluffy black fur with white paws and belly.
In this example the "http://example.org/animals#cat" item has three properties, a "name" ("Hedral"), a
"desc" ("Hedral is..."), and an "img" ("hedral.jpeg").
An item can only have one type. The type gives the context for the properties, thus defining a vocabulary: a
property named "class" given for an item with the type "http://census.example/person" might refer to the
economic class of an individual, while a property named "class" given for an item with the type
"http://example.com/school/teacher" might refer to the classroom a teacher has been assigned.
5.1.4 Global identifiers for items
This section is non-normative.
Sometimes, an item p405 gives information about a topic that has a global identifier. For example, books can be
identified by their ISBN number.
Vocabularies (as identified by the itemtype p405 attribute) can be designed such that items p405 get associated with
their global identifier in an unambiguous way by expressing the global identifiers as URLs p51 given in an itemid p405
attribute.
The exact meaning of the URLs p51 given in itemid p405 attributes depends on the vocabulary used.
Here, an item is talking about a particular book:
Title
The Reality Dysfunction
Author
Peter F. Hamilton
Publication date
26 January 1996
The "http://vocab.example.net/book" vocabulary in this example would define that the itemid p405
attribute takes a urn: URL p51 pointing to the ISBN of the book.
5.1.5 Selecting names when defining vocabularies
This section is non-normative.
Using microdata means using a vocabulary. For some purposes, an ad-hoc vocabulary is adequate. For others, a
vocabulary will need to be designed. Where possible, authors are encouraged to re-use existing vocabularies, as
this makes content re-use easier.
When designing new vocabularies, identifiers can be created either using URLs p51 , or, for properties, as plain
words (with no dots or colons). For URLs, conflicts with other vocabularies can be avoided by only using identifiers
that correspond to pages that the author has control over.
402
For instance, if Jon and Adam both write content at example.com, at http://example.com/~jon/... and
http://example.com/~adam/... respectively, then they could select identifiers of the form
"http://example.com/~jon/name" and "http://example.com/~adam/name" respectively.
Properties whose names are just plain words can only be used within the context of the types for which they are
intended; properties named using URLs can be reused in items of any type. If an item has no type, and is not part
of another item, then if its properties have names that are just plain words, they are not intended to be globally
unique, and are instead only intended for limited use. Generally speaking, authors are encouraged to use either
properties with globally unique names (URLs) or ensure that their items are typed.
Here, an item is an "http://example.org/animals#cat", and most of the properties have names that are
words defined in the context of that type. There are also a few additional properties whose names come
from other vocabularies.
Hedral
Hedral is a male american domestic
shorthair, with a fluffy black fur with white paws and belly.
This example has one item with the type "http://example.org/animals#cat" and the following properties:
Property
Value
name
Hedral
http://example.com/fn
Hedral
desc
Hedral is a male american domestic shorthair, with a fluffy black fur with white paws and belly.
http://example.com/color black
http://example.com/color white
img
.../hedral.jpeg
5.1.6 Using the microdata DOM API
This section is non-normative.
The microdata becomes even more useful when scripts can use it to expose information to the user, for example
offering it in a form that can be used by other applications.
The document.getItems(typeNames) p409 method provides access to the top-level microdata items p407 . It returns a
NodeList p31 containing the items with the specified types, or all types if no argument is specified.
Each item p405 is represented in the DOM by the element on which the relevant itemscope p405 attribute is found.
These elements have their element.itemScope p409 IDL attribute set to true.
The type of items p405 can be obtained using the element.itemType p409 IDL attribute on the element with the
itemscope p405 attribute.
This sample shows how the getItems() p409 method can be used to obtain a list of all the top-level
microdata items of one type given in the document:
var cats = document.getItems("http://example.com/feline");
Once an element representing an item p405 has been obtained, its properties can be extracted using the
properties p409 IDL attribute. This attribute returns an HTMLPropertiesCollection p64 , which can be enumerated
to go through each element that adds one or more properties to the item. It can also be indexed by name, which
will return an object with a list of the elements that add properties with that name.
Each element that adds a property also has a itemValue p409 IDL attribute that returns its value.
This sample gets the first item of type "http://example.net/user" and then pops up an alert using the "name"
property from that item.
var user = document.getItems('http://example.net/user')[0];
alert('Hello ' + user.properties['name'][0].content + '!');
The HTMLPropertiesCollection p64 object, when indexed by name in this way, actually returns a
PropertyNodeList p64 object with all the matching properties. The PropertyNodeList p64 object can be used to
obtain all the values at once using its values p65 attribute, which returns an array of all the values.
403
In an earlier example, a "http://example.org/animals#cat" item had two "http://example.com/color" values.
This script looks up the first such item and then lists all its values.
var cat = document.getItems('http://example.org/animals#cat')[0];
var colors = cat.properties['http://example.com/color'].values;
var result;
if (colors.length == 0) {
result = 'Color unknown.';
} else if (colors.length == 1) {
result = 'Color: ' + colors[0];
} else {
result = 'Colors:';
for (var i = 0; i < colors.length; i += 1)
result += ' ' + colors[i];
}
It's also possible to get a list of all the property names p406 using the object's names p65 IDL attribute.
This example creates a big list with a nested list for each item on the page, each with of all the property
names used in that item.
var outer = document.createElement('ul');
var items = document.getItems();
for (var item = 0; item < items.length; item += 1) {
var itemLi = document.createElement('li');
var inner = document.createElement('ul');
for (var name = 0; name < items[item].properties.names.length; name += 1) {
var propLi = document.createElement('li');
propLi.appendChild(document.createTextNode(items[item].properties.names[name]));
inner.appendChild(propLi);
}
itemLi.appendChild(inner);
outer.appendChild(itemLi);
}
document.body.appendChild(outer);
If faced with the following from an earlier example:
Hedral
Hedral is a male american domestic
shorthair, with a fluffy black fur with white paws and belly.
...it would result in the following output:
•
•
•
•
•
•
name
http://example.com/fn
desc
http://example.com/color
img
(The duplicate occurrence of "http://example.com/color" is not included in the list.)
5.2 Encoding microdata
5.2.1 The microdata model
The microdata model consists of groups of name-value pairs known as items p405 .
Each group is known as an item p405 . Each item p405 can have an item type p405 , a global identifier p405 (if the item
type p405 supports global identifiers for its items p405 ), and a list of name-value pairs. Each name in the name-value
pair is known as a property p407 , and each property p407 has one or more values p406 . Each value p406 is either a string
or itself a group of name-value pairs (an item p405 ).
An item p405 is said to be a typed item when either it has an item type p405 , or it is the value p406 of a property p407 of
a typed item p404 . The relevant type for a typed item p404 is the item p405 's item type p405 , if it has one, or else is the
relevant type p404 of the item p405 for which it is a property p407 's value p406 .
404
5.2.2 Items
Every HTML element p26 may have an itemscope attribute specified. The itemscope p405 attribute is a boolean
attribute p34 .
An element with the itemscope p405 attribute specified creates a new item, a group of name-value pairs.
Elements with an itemscope p405 attribute may have an itemtype attribute specified, to give the item type p405 of
the item p405 .
The itemtype p405 attribute, if specified, must have a value that is a valid URL p51 that is an absolute URL p52 for
which the string "http://www.w3.org/1999/xhtml/microdata#" is not a prefix match p33 .
The item type of an item p405 is the value of its element's itemtype p405 attribute, if it has one and its value is not
the empty string. If the itemtype p405 attribute is missing or its value is the empty string, the item p405 is said to
have no item type p405 .
The item type p405 must be a type defined in an applicable specification p33 .
Except if otherwise specified by that specification, the URL p51 given as the item type p405 should not be
automatically dereferenced.
Note: A specification could define that its item type p405 can be derefenced to provide the user
with help information, for example. In fact, vocabulary authors are encouraged to provide
useful information at the given URL p51 .
Item types p405 are opaque identifiers, and user agents must not dereference unknown item types p405 , or otherwise
deconstruct them, in order to determine how to process items p405 that use them.
The itemtype p405 attribute must not be specified on elements that do not have an itemscope p405 attribute
specified.
Elements with an itemscope p405 attribute and an itemtype p405 attribute that references a vocabulary that is
defined to support global identifiers for items may also have an itemid attribute specified, to give a global
identifier for the item p405 , so that it can be related to other items p405 on pages elsewhere on the Web.
The itemid p405 attribute, if specified, must have a value that is a valid URL p51 .
The global identifier of an item p405 is the value of its element's itemid p405 attribute, if it has one, resolved p51
relative to the element on which the attribute is specified. If the itemid p405 attribute is missing or if resolving it
fails, it is said to have no global identifier p405 .
The itemid p405 attribute must not be specified on elements that do not have both an itemscope p405 attribute and
an itemtype p405 attribute specified, and must not be specified on elements with an itemscope p405 attribute whose
itemtype p405 attribute specifies a vocabulary that does not support global identifiers for items p405 , as defined by
that vocabulary's specification.
Elements with an itemscope p405 attribute may have an itemref attribute specified, to give a list of additional
elements to crawl to find the name-value pairs of the item p405 .
The itemref p405 attribute, if specified, must have a value that is an unordered set of unique space-separated
tokens p49 consisting of IDs p84 of elements in the same home subtree p27 .
The itemref p405 attribute must not be specified on elements that do not have an itemscope p405 attribute specified.
5.2.3 Names: the itemprop attribute
Every HTML element p26 may have an itemprop p405 attribute specified, if doing so adds a property p407 to one or
more items p405 (as defined below).
The itemprop p405 attribute, if specified, must have a value that is an unordered set of unique space-separated
tokens p49 representing the names of the name-value pairs that it adds. The attribute's value must have at least
one token.
Each token must be either:
•
A valid URL p51 that is an absolute URL p52 for which the string "http://www.w3.org/1999/xhtml/
microdata#" is not a prefix match p33 , or
405
•
If the item is a typed item p404 : a defined property name allowed in this situation according to the
specification that defines the relevant type p404 for the item, or
•
If the item is not a typed item p404 : a string that contains no U+002E FULL STOP characters (.) and no
U+003A COLON characters (:).
When an element with an itemprop attribute adds a property p407 to multiple items p405 , the requirement above
regarding the tokens applies for each item p405 individually.
The property names of an element are the tokens that the element's itemprop p405 attribute is found to contain
when its value is split on spaces p49 , with the order preserved but with duplicates removed (leaving only the first
occurrence of each name).
Within an item p405 , the properties are unordered with respect to each other, except for properties with the same
name, which are ordered in the order they are given by the algorithm that defines the properties of an item p407 .
In the following example, the "a" property has the values "1" and "2", in that order, but whether the "a"
property comes before the "b" property or not is not important:
Thus, the following is equivalent:
As is the following:
And the following:
5.2.4 Values
The property value of a name-value pair added by an element with an itemprop p405 attribute depends on the
element, as follows:
If the element also has an itemscope p405 attribute
The value is the item p405 created by the element.
If the element is a meta p112 element
The value is the value of the element's content attribute, if any, or the empty string if there is no such
attribute.
If the element is an audio p216 , embed p205 , iframe p199 , img p186 , source p217 , or video p213 element
The value is the absolute URL p52 that results from resolving p51 the value of the element's src attribute
relative to the element at the time the attribute is set, or the empty string if there is no such attribute or if
resolving p51 it results in an error.
If the element is an a p160 , area p266 , or link p109 element
The value is the absolute URL p52 that results from resolving p51 the value of the element's href attribute
relative to the element at the time the attribute is set, or the empty string if there is no such attribute or if
resolving p51 it results in an error.
406
If the element is an object p208 element
The value is the absolute URL p52 that results from resolving p51 the value of the element's data attribute
relative to the element at the time the attribute is set, or the empty string if there is no such attribute or if
resolving p51 it results in an error.
If the element is a time p168 element with a datetime p169 attribute
The value is the value of the element's datetime p169 attribute.
Otherwise
The value is the element's textContent p31 .
The URL property elements are the a p160 , area p266 , audio p216 , embed p205 , iframe p199 , img p186 , link p109 , object p208 ,
source p217 , and video p213 elements.
If a property's value p406 is an absolute URL p52 , the property must be specified using a URL property element p407 .
If a property's value p406 represents a date p41 , time p42 , or global date and time p44 , the property must be specified
using the datetime p169 attribute of a time p168 element.
5.2.5 Associating names with items
To find the properties of an item defined by the element root, the user agent must try to crawl the
properties p407 of the element root, with an empty list as the value of memory: if this fails, then the properties of
the item p407 defined by the element root is an empty list; otherwise, it is the returned list.
To crawl the properties of an element root with a list memory, the user agent must run the following steps.
These steps either fail or return a list with a count of errors. The count of errors is used as part of the authoring
conformance criteria below.
1.
If root is in memory, then the algorithm fails; abort these steps.
2.
Collect all the elements in the item p407 root; let results be the resulting list of elements, and errors be
the resulting count of errors.
3.
Remove any elements from results that do not have an itemprop p405 attribute specified.
4.
Let new memory be a new list consisting of the old list memory with the addition of root.
5.
For each element in results that has an itemscope p405 attribute specified, crawl the properties p407 of the
element, with new memory as the memory. If this fails, then remove the element from results and
increment errors. (If it succeeds, the return value is discarded.)
6.
Sort results in tree order p27 .
7.
Return results and errors.
To collect all the elements in the item root, the user agent must run these steps. They return a list of elements
and a count of errors.
1.
Let results and pending be empty lists of elements.
2.
Let errors be zero.
3.
Add all the children elements of root to pending.
4.
If root has an itemref p405 attribute, split the value of that itemref attribute on spaces p49 . For each
resulting token ID, if there is an element in the home subtree p27 of root with the ID p84 ID, then add the
first such element to pending.
5.
Loop: Remove an element from pending and let current be that element.
6.
If current is already in results, increment errors.
7.
If current is not already in results and current does not have an itemscope p405 attribute, then: add all the
child elements of current to pending.
8.
If current is not already in results, then: add current to results.
9.
End of loop: If pending is not empty, return to the step labeled loop.
10.
Return results and errors.
An item p405 is a top-level microdata item if its element does not have an itemprop p405 attribute.
407
An item p405 is a used microdata item if it is a top-level microdata item p407 , or if it has an itemprop p405 attribute
and would be found to be the property p407 of an item p405 that is itself a used microdata item p408 .
A document must not contain any items p405 that are not used microdata items p408 .
A document must not contain any elements that have an itemprop p405 attribute that would not be found to be a
property of any of the items p405 in that document were their properties p407 all to be determined.
A document must not contain any items p405 for which crawling the properties p407 of the element, with an empty list
as the value of memory, either fails or returns an error count other than zero.
Note: The algorithms in this section are especially inefficient, in the interests of keeping them
easy to understand. Implementors are strongly encouraged to refactor and optimize them in
their user agents.
In this example, a single license statement is applied to two works, using itemref p405 from the items
representing the works:
Photo gallery
My photos
The house I found.
The mailbox.
The above results in two items with the type "http://n.whatwg.org/work", one with:
work
images/house.jpeg
title
The house I found.
license
http://www.opensource.org/licenses/mit-license.php
...and one with:
work
images/mailbox.jpeg
title
The mailbox.
license
http://www.opensource.org/licenses/mit-license.php
5.3 Microdata DOM API
This box is non-normative. Implementation requirements are given below this box.
408
document . getItems p409 ( [ types ] )
Returns a NodeList p31 of the elements in the Document p31 that create items p405 , that are not part of
other items p405 , and that are of one of the types given in the argument, if any are listed.
The types argument is interpreted as a space-separated list of types.
element . properties p409
If the element has an itemscope p405 attribute, returns an HTMLPropertiesCollection p64 object with
all the element's properties. Otherwise, an empty HTMLPropertiesCollection p64 object.
element . itemValue p409 [ = value ]
Returns the element's value p406 .
Can be set, to change the element's value p406 . Setting the value p406 when the element has no
itemprop p405 attribute or when the element's value is an item p405 throws an INVALID_ACCESS_ERR p70
exception.
The document.getItems(typeNames) method takes an optional string that contains an unordered set of unique
space-separated tokens p49 representing types. When called, the method must return a live p27 NodeList p31 object
containing all the elements in the document, in tree order p27 , that are each top-level microdata items p407 with a
type p405 equal to one of the types specified in that argument, having obtained the types by splitting the string on
spaces p49 . If there are no tokens specified in the argument, or if the argument is missing, then the method must
return a NodeList p31 containing all the top-level microdata items p407 in the document. When the method is invoked
on a Document p31 object again with the same argument, the user agent may return the same object as the object
returned by the earlier call. In other cases, a new NodeList p31 object must be returned.
The itemScope IDL attribute on HTML elements p26 must reflect p57 the itemscope p405 content attribute. The
itemType IDL attribute on HTML elements p26 must reflect p57 the itemtype p405 content attribute, as if it was a
regular string attribute, not a URL p51 string attribute. The itemId IDL attribute on HTML elements p26 must reflect p57
the itemid p405 content attribute. The itemProp IDL attribute on HTML elements p26 must reflect p57 the itemprop p405
content attribute. The itemRef IDL attribute on HTML elements p26 must reflect p57 the itemref p405 content
attribute.
The properties IDL attribute on HTML elements p26 must return an HTMLPropertiesCollection p64 rooted at the
Document p31 node, whose filter matches only elements that have property names p406 and are the properties of the
item p407 created by the element on which the attribute was invoked, while that element is an item p405 , and
matches nothing the rest of the time.
The itemValue IDL attribute's behavior depends on the element, as follows:
If the element has no itemprop p405 attribute
The attribute must return null on getting and must throw an INVALID_ACCESS_ERR p70 exception on setting.
If the element has an itemscope p405 attribute
The attribute must return the element itself on getting and must throw an INVALID_ACCESS_ERR p70 exception
on setting.
If the element is a meta p112 element
The attribute must act as it would if it was reflecting p57 the element's content p113 content attribute.
If the element is an audio p216 , embed p205 , iframe p199 , img p186 , source p217 , or video p213 element
The attribute must act as it would if it was reflecting p57 the element's src content attribute.
If the element is an a p160 , area p266 , or link p109 element
The attribute must act as it would if it was reflecting p57 the element's href content attribute.
If the element is an object p208 element
The attribute must act as it would if it was reflecting p57 the element's data content attribute.
If the element is a time p168 element with a datetime p169 attribute
The attribute must act as it would if it was reflecting p57 the element's datetime p169 content attribute.
Otherwise
The attribute must act the same as the element's textContent p31 attribute.
When the itemValue p409 IDL attribute is reflecting p57 a content attribute or acting like the element's
textContent p31 attribute, the user agent must, on setting, convert the new value to the IDL DOMString value
before using it according to the mappings described above.
409
In this example, a script checks to see if a particular element element is declaring a particular property, and if it is,
it increments a counter:
if (element.itemProp.contains('color'))
count += 1;
This script iterates over each of the values of an element's itemref p405 attribute, calling a function for each
referenced element:
for (var index = 0; index < element.itemRef.length; index += 1)
process(document.getElementById(element.itemRef[index]));
5.4 Microdata vocabularies
5.4.1 vCard
An item with the item type p405 http://microformats.org/profile/hcard represents a person's or organization's
contact information.
This vocabulary supports global identifiers for items p405 .
The following are the type's defined property names p406 . They are based on the vocabulary defined in the vCard
specification and its extensions, where more information on how to interpret the values can be found.
[RFC2426] p703 [RFC4770] p703
fn
Gives the formatted text corresponding to the name of the person or organization.
The value p406 must be text.
Exactly one property with the name fn p410 must be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
n
Gives the structured name of the person or organization.
The value p406 must be an item p405 with zero or more of each of the family-name p410 , given-name p410 ,
additional-name p410 , honorific-prefix p410 , and honorific-suffix p411 properties.
Exactly one property with the name n p410 must be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
family-name (inside n p410 )
Gives the family name of the person, or the full name of the organization.
The value p406 must be text.
Any number of properties with the name family-name p410 may be present within the item p405 that forms the
value p406 of the n p410 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
given-name (inside n p410 )
Gives the given-name of the person.
The value p406 must be text.
Any number of properties with the name given-name p410 may be present within the item p405 that forms the
value p406 of the n p410 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
additional-name (inside n p410 )
Gives the any additional names of the person.
The value p406 must be text.
Any number of properties with the name additional-name p410 may be present within the item p405 that forms
the value p406 of the n p410 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
honorific-prefix (inside n p410 )
Gives the honorific prefix of the person.
The value p406 must be text.
410
Any number of properties with the name honorific-prefix p410 may be present within the item p405 that
forms the value p406 of the n p410 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
honorific-suffix (inside n p410 )
Gives the honorific suffix of the person.
The value p406 must be text.
Any number of properties with the name honorific-suffix p411 may be present within the item p405 that
forms the value p406 of the n p410 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
nickname
Gives the nickname of the person or organization.
Note: The nickname is the descriptive name given instead of or in addition to the one
belonging to a person, place, or thing. It can also be used to specify a familiar form of a
proper name specified by the fn p410 or n p410 properties.
The value p406 must be text.
Any number of properties with the name nickname p411 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
photo
Gives a photograph of the person or organization.
The value p406 must be an absolute URL p52 .
Any number of properties with the name photo p411 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
bday
Gives the birth date of the person or organization.
The value p406 must be a valid date string p41 .
A single property with the name bday p411 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
adr
Gives the delivery address of the person or organization.
The value p406 must be an item p405 with zero or more type p411 , post-office-box p411 , extended-address p412 ,
and street-address p412 properties, and optionally a locality p412 property, optionally a region p412 property,
optionally a postal-code p412 property, and optionally a country-name p412 property.
If no type p411 properties are present within an item p405 that forms the value p406 of an adr p411 property of an
item p405 with the type http://microformats.org/profile/hcard p410 , then the address type strings p417
intl, postal, parcel, and work are implied.
Any number of properties with the name adr p411 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
type (inside adr p411 )
Gives the type of delivery address.
The value p406 must be text that, when compared in a case-sensitive p33 manner, is equal to one of the address
type strings p417 .
Within each item p405 with the type http://microformats.org/profile/hcard p410 , there must be no more
than one adr p411 property item p405 with a type p411 property whose value is pref p417 .
Any number of properties with the name type p411 may be present within the item p405 that forms the value p406
of an adr p411 property of an item p405 with the type http://microformats.org/profile/hcard p410 , but within
each such adr p411 property item p405 there must only be one type p411 property per distinct value.
post-office-box (inside adr p411 )
Gives the post office box component of the delivery address of the person or organization.
The value p406 must be text.
411
Any number of properties with the name post-office-box p411 may be present within the item p405 that forms
the value p406 of an adr p411 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
extended-address (inside adr p411 )
Gives an additional component of the delivery address of the person or organization.
The value p406 must be text.
Any number of properties with the name extended-address p412 may be present within the item p405 that
forms the value p406 of an adr p411 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
street-address (inside adr p411 )
Gives the street address component of the delivery address of the person or organization.
The value p406 must be text.
Any number of properties with the name street-address p412 may be present within the item p405 that forms
the value p406 of an adr p411 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
locality (inside adr p411 )
Gives the locality component (e.g. city) of the delivery address of the person or organization.
The value p406 must be text.
A single property with the name locality p412 may be present within the item p405 that forms the value p406 of
an adr p411 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
region (inside adr p411 )
Gives the region component (e.g. state or province) of the delivery address of the person or organization.
The value p406 must be text.
A single property with the name region p412 may be present within the item p405 that forms the value p406 of an
adr p411 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
postal-code (inside adr p411 )
Gives the postal code component of the delivery address of the person or organization.
The value p406 must be text.
A single property with the name postal-code p412 may be present within the item p405 that forms the value p406
of an adr p411 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
country-name (inside adr p411 )
Gives the country name component of the delivery address of the person or organization.
The value p406 must be text.
A single property with the name country-name p412 may be present within the item p405 that forms the
value p406 of an adr p411 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
label
Gives the formatted text corresponding to the delivery address of the person or organization.
The value p406 must be either text or an item p405 with zero or more type p412 properties and exactly one
value p413 property.
If no type p412 properties are present within an item p405 that forms the value p406 of a label p412 property of an
item p405 with the type http://microformats.org/profile/hcard p410 , or if the value p406 of such a label p412
property is text, then the address type strings p417 intl, postal, parcel, and work are implied.
Any number of properties with the name label p412 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
type (inside label p412 )
Gives the type of delivery address.
The value p406 must be text that, when compared in a case-sensitive p33 manner, is equal to one of the address
type strings p417 .
412
Within each item p405 with the type http://microformats.org/profile/hcard p410 , there must be no more
than one label p412 property item p405 with a type p412 property whose value is pref p417 .
Any number of properties with the name type p412 may be present within the item p405 that forms the value p406
of a label p412 property of an item p405 with the type http://microformats.org/profile/hcard p410 , but
within each such label p412 property item p405 there must only be one type p412 property per distinct value.
value (inside label p412 )
Gives the actual formatted text corresponding to the delivery address of the person or organization.
The value p406 must be text.
Exactly one property with the name value p413 must be present within the item p405 that forms the value p406 of
a label p412 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
tel
Gives the telephone number of the person or organization.
The value p406 must be either text that can be interpreted as a telephone number as defined in the CCITT
specifications E.163 and X.121, or an item p405 with zero or more type p413 properties and exactly one
value p413 property. [E163] p701 [X121] p704
If no type p413 properties are present within an item p405 that forms the value p406 of a tel p413 property of an
item p405 with the type http://microformats.org/profile/hcard p410 , or if the value p406 of such a tel p413
property is text, then the telephone type string p417 voice is implied.
Any number of properties with the name tel p413 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
type (inside tel p413 )
Gives the type of telephone number.
The value p406 must be text that, when compared in a case-sensitive p33 manner, is equal to one of the
telephone type strings p417 .
Within each item p405 with the type http://microformats.org/profile/hcard p410 , there must be no more
than one tel p413 property item p405 with a type p413 property whose value is pref p418 .
Any number of properties with the name type p413 may be present within the item p405 that forms the value p406
of a tel p413 property of an item p405 with the type http://microformats.org/profile/hcard p410 , but within
each such tel p413 property item p405 there must only be one type p413 property per distinct value.
value (inside tel p413 )
Gives the actual telephone number of the person or organization.
The value p406 must be text that can be interpreted as a telephone number as defined in the CCITT
specifications E.163 and X.121. [E163] p701 [X121] p704
Exactly one property with the name value p413 must be present within the item p405 that forms the value p406 of
a tel p413 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
email
Gives the e-mail address of the person or organization.
The value p406 must be either text or an item p405 with zero or more type p413 properties and exactly one
value p414 property.
If no type p413 properties are present within an item p405 that forms the value p406 of an email p413 property of an
item p405 with the type http://microformats.org/profile/hcard p410 , or if the value p406 of such an email p413
property is text, then the e-mail type string p418 internet is implied.
Any number of properties with the name email p413 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
type (inside email p413 )
Gives the type of e-mail address.
The value p406 must be text that, when compared in a case-sensitive p33 manner, is equal to one of the e-mail
type strings p418 .
Within each item p405 with the type http://microformats.org/profile/hcard p410 , there must be no more
than one email p413 property item p405 with a type p413 property whose value is pref p418 .
413
Any number of properties with the name type p413 may be present within the item p405 that forms the value p406
of an email p413 property of an item p405 with the type http://microformats.org/profile/hcard p410 , but
within each such email p413 property item p405 there must only be one type p413 property per distinct value.
value (inside email p413 )
Gives the actual e-mail address of the person or organization.
The value p406 must be text.
Exactly one property with the name value p414 must be present within the item p405 that forms the value p406 of
an email p413 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
mailer
Gives the name of the e-mail software used by the person or organization.
The value p406 must be text.
Any number of properties with the name mailer p414 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
tz
Gives the time zone of the person or organization.
The value p406 must be text and must match the following syntax:
1.
Either a U+002B PLUS SIGN character (+) or a U+002D HYPHEN-MINUS character (-).
2.
A valid non-negative integer p35 that is exactly two digits long and that represents a number in the
range 00..23.
3.
A U+003A COLON character (:).
4.
A valid non-negative integer p35 that is exactly two digits long and that represents a number in the
range 00..59.
Any number of properties with the name tz p414 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
geo
Gives the geographical position of the person or organization.
The value p406 must be text and must match the following syntax:
1.
Optionally, either a U+002B PLUS SIGN character (+) or a U+002D HYPHEN-MINUS character (-).
2.
One or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
3.
Optionally*, a U+002E FULL STOP character (.) followed by one or more digits in the range U+0030
DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
4.
A U+003B SEMICOLON character (;).
5.
Optionally, either a U+002B PLUS SIGN character (+) or a U+002D HYPHEN-MINUS character (-).
6.
One or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
7.
Optionally*, a U+002E FULL STOP character (.) followed by one or more digits in the range U+0030
DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
The optional components marked with an asterisk (*) should be included, and should have six digits each.
Note: The value specifies latitude and longitude, in that order (i.e., "LAT LON" ordering),
in decimal degrees. The longitude represents the location east and west of the prime
meridian as a positive or negative real number, respectively. The latitude represents the
location north and south of the equator as a positive or negative real number,
respectively.
Any number of properties with the name geo p414 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
title
Gives the job title, functional position or function of the person or organization.
The value p406 must be text.
414
Any number of properties with the name title p414 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
role
Gives the role, occupation, or business category of the person or organization.
The value p406 must be text.
Any number of properties with the name role p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
logo
Gives the logo of the person or organization.
The value p406 must be an absolute URL p52 .
Any number of properties with the name logo p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
agent
Gives the contact information of another person who will act on behalf of the person or organization.
The value p406 must be either an item p405 with the type http://microformats.org/profile/hcard p410 , or an
absolute URL p52 , or text.
Any number of properties with the name agent p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
org
Gives the name and units of the organization.
The value p406 must be either text or an item p405 with one organization-name p415 property and zero or more
organization-unit properties.
Any number of properties with the name org p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
organization-name (inside org p415 )
Gives the name of the organization.
The value p406 must be text.
Exactly one property with the name organization-name p415 must be present within the item p405 that forms
the value p406 of an org p415 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
organization-unit (inside org p415 )
Gives the name of the organization unit.
The value p406 must be text.
Any number of properties with the name organization-unit p415 may be present within the item p405 that
forms the value p406 of the org p415 property of an item p405 with the type http://microformats.org/profile/
hcard p410 .
categories
Gives the name of a category or tag that the person or organization could be classified as.
The value p406 must be text.
Any number of properties with the name categories p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
note
Gives supplemental information or a comment about the person or organization.
The value p406 must be text.
Any number of properties with the name note p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
rev
Gives the revision date and time of the contact information.
415
The value p406 must be text that is a valid global date and time string p44 .
Note: The value distinguishes the current revision of the information for other renditions
of the information.
Any number of properties with the name rev p415 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
sort-string
Gives the string to be used for sorting the person or organization.
The value p406 must be text.
Any number of properties with the name sort-string p416 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
sound
Gives a sound file relating to the person or organization.
The value p406 must be an absolute URL p52 .
Any number of properties with the name sound p416 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
url
Gives a URL p51 relating to the person or organization.
The value p406 must be an absolute URL p52 .
Any number of properties with the name url p416 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
class
Gives the access classification of the information regarding the person or organization.
The value p406 must be text with one of the following values:
•
•
•
public
private
confidential
⚠Warning! This is merely advisory and cannot be considered a confidentiality measure.
Any number of properties with the name class p416 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
impp
Gives a URL p51 for instant messaging and presence protocol communications with the person or organization.
The value p406 must be either an absolute URL p52 or an item p405 with zero or more type p416 properties and
exactly one value p417 property.
If no type p416 properties are present within an item p405 that forms the value p406 of an impp p416 property of an
item p405 with the type http://microformats.org/profile/hcard p410 , or if the value p406 of such an impp p416
property is an absolute URL p52 , then no IMPP type strings p418 are implied.
Any number of properties with the name impp p416 may be present within each item p405 with the type
http://microformats.org/profile/hcard p410 .
type (inside impp p416 )
Gives the intended use of the IMPP URL p51 .
The value p406 must be text that, when compared in a case-sensitive p33 manner, is equal to one of the IMPP
type strings p418 .
Within each item p405 with the type http://microformats.org/profile/hcard p410 , there must be no more
than one impp p416 property item p405 with a type p416 property whose value is pref p418 .
Any number of properties with the name type p416 may be present within the item p405 that forms the value p406
of an impp p416 property of an item p405 with the type http://microformats.org/profile/hcard p410 , but
within each such impp p416 property item p405 there must only be one type p416 property per distinct value.
416
value (inside impp p416 )
Gives the actual URL p51 for instant messaging and presence protocol communications with the person or
organization.
The value p406 must be an absolute URL p52 .
Exactly one property with the name value p417 must be present within the item p405 that forms the value p406 of
an impp p416 property of an item p405 with the type http://microformats.org/profile/hcard p410 .
The address type strings are:
dom
Indicates a domestic delivery address.
intl
Indicates an international delivery address.
postal
Indicates a postal delivery address.
parcel
Indicates a parcel delivery address.
home
Indicates a residential delivery address.
work
Indicates a delivery address for a place of work.
pref
Indicates the preferred delivery address when multiple addresses are specified.
The telephone type strings are:
home
Indicates a residential number.
msg
Indicates a telephone number with voice messaging support.
work
Indicates a telephone number for a place of work.
voice
Indicates a voice telephone number.
fax
Indicates a facsimile telephone number.
cell
Indicates a cellular telephone number.
video
Indicates a video conferencing telephone number.
pager
Indicates a paging device telephone number.
bbs
Indicates a bulletin board system telephone number.
modem
Indicates a MODEM-connected telephone number.
car
Indicates a car-phone telephone number.
isdn
Indicates an ISDN service telephone number.
pcs
Indicates a personal communication services telephone number.
417
pref
Indicates the preferred telephone number when multiple telephone numbers are specified.
The e-mail type strings are:
internet
Indicates an Internet e-mail address.
x400
Indicates a X.400 addressing type.
pref
Indicates the preferred e-mail address when multiple e-mail addresses are specified.
The IMPP type strings are:
personal
business
Indicates the type of communication for which this IMPP URL p51 is appropriate.
home
work
mobile
Indicates the location of a device associated with this IMPP URL p51 .
pref
Indicates the preferred address when multiple IMPP URL p51 s are specified.
5.4.1.1 Conversion to vCard
Given a list of nodes nodes in a Document p31 , a user agent must run the following algorithm to extract any vCard
data represented by those nodes (only the first vCard is returned):
1.
If none of the nodes in nodes are items p405 with the item type p405 http://microformats.org/profile/
hcard p410 , then there is no vCard. Abort the algorithm, returning nothing.
2.
Let node be the first node in nodes that is an item p405 with the item type p405
http://microformats.org/profile/hcard p410 .
3.
Let output be an empty string.
4.
Add a vCard line p420 with the type "BEGIN" and the value "VCARD" to output.
5.
Add a vCard line p420 with the type "PROFILE" and the value "VCARD" to output.
6.
Add a vCard line p420 with the type "VERSION" and the value "3.0" to output.
7.
Add a vCard line p420 with the type "SOURCE" and the result of escaping the vCard text string p421 that is
the document's current address p71 as the value to output.
8.
If the title element p76 is not null, add a vCard line p420 with the type "NAME" and with the result of
escaping the vCard text string p421 obtained from the textContent p31 of the title element p76 as the
value to output.
9.
If node has a global identifier p405 , add a vCard line p420 with the type "UID" and with the result of escaping
the vCard text string p421 of that global identifier p405 as the value to output.
10.
For each element element that is a property of the item p407 node: for each name name in element's
property names p406 , run the following substeps:
1.
Let parameters be an empty set of name-value pairs.
2.
Run the appropriate set of substeps from the following list. The steps will set a variable value,
which is used in the next step.
If the property's value p406 is an item p405 subitem and name is n p410
418
1.
Let value be the empty string.
2.
Append to value the result of collecting the first vCard subproperty p421 named
family-name p410 in subitem.
3.
Append a U+003B SEMICOLON character (;) to value.
4.
Append to value the result of collecting the first vCard subproperty p421 named
given-name p410 in subitem.
5.
Append a U+003B SEMICOLON character (;) to value.
6.
Append to value the result of collecting the first vCard subproperty p421 named
additional-name p410 in subitem.
7.
Append a U+003B SEMICOLON character (;) to value.
8.
Append to value the result of collecting the first vCard subproperty p421 named
honorific-prefix p410 in subitem.
9.
Append a U+003B SEMICOLON character (;) to value.
10.
Append to value the result of collecting the first vCard subproperty p421 named
honorific-suffix p411 in subitem.
If the property's value p406 is an item p405 subitem and name is adr p411
1.
Let value be the empty string.
2.
Append to value the result of collecting vCard subproperties p421 named postoffice-box p411 in subitem.
3.
Append a U+003B SEMICOLON character (;) to value.
4.
Append to value the result of collecting vCard subproperties p421 named
extended-address p412 in subitem.
5.
Append a U+003B SEMICOLON character (;) to value.
6.
Append to value the result of collecting vCard subproperties p421 named
street-address p412 in subitem.
7.
Append a U+003B SEMICOLON character (;) to value.
8.
Append to value the result of collecting the first vCard subproperty p421 named
locality p412 in subitem.
9.
Append a U+003B SEMICOLON character (;) to value.
10.
Append to value the result of collecting the first vCard subproperty p421 named
region p412 in subitem.
11.
Append a U+003B SEMICOLON character (;) to value.
12.
Append to value the result of collecting the first vCard subproperty p421 named
postal-code p412 in subitem.
13.
Append a U+003B SEMICOLON character (;) to value.
14.
Append to value the result of collecting the first vCard subproperty p421 named
country-name p412 in subitem.
15.
If there is a property named type p411 in subitem, and the first such property
has a value p406 that is not an item p405 and whose value consists only of
alphanumeric ASCII characters p34 , then add a parameter named "TYPE" whose
value is the value p406 of that property to parameters.
If the property's value p406 is an item p405 subitem and name is org p415
1.
Let value be the empty string.
2.
Append to value the result of collecting the first vCard subproperty p421 named
organization-name p415 in subitem.
3.
For each property named organization-unit p415 in subitem, run the following
steps:
1.
If the value p406 of the property is an item p405 , then skip this property.
2.
Append a U+003B SEMICOLON character (;) to value.
3.
Append the result of escaping the vCard text string p421 given by the
value p406 of the property to value.
419
If the property's value p406 is an item p405 subitem with the item type p405
http://microformats.org/profile/hcard p410 and name is agent p415
1.
Let value be the result of escaping the vCard text string p421 obtained from
extracting a vCard p418 from the element that represents subitem.
2.
Add a parameter named "VALUE" whose value is "VCARD" to parameters.
If the property's value p406 is an item p405 and name is none of the above
1.
Let value be the result of collecting the first vCard subproperty p421 named
value in subitem.
2.
If there is a property named type in subitem, and the first such property has a
value p406 that is not an item p405 and whose value consists only of alphanumeric
ASCII characters p34 , then add a parameter named "TYPE" whose value is the
value p406 of that property to parameters.
Otherwise (the property's value p406 is not an item p405 )
3.
11.
1.
Let value be the property's value p406 .
2.
If element is one of the URL property elements p407 , add a parameter with the
name "VALUE" and the value "URI" to parameters.
3.
Otherwise, if element is a time p168 element and the value is a valid date
string p41 , add a parameter with the name "VALUE" and the value "DATE" to
parameters.
4.
Otherwise, if element is a time p168 element and the value is a valid global date
and time string p44 , add a parameter with the name "VALUE" and the value
"DATE-TIME" to parameters.
5.
Prefix every U+005C REVERSE SOLIDUS character (\) in value with another
U+005C REVERSE SOLIDUS character (\).
6.
Prefix every U+002C COMMA character (,) in value with a U+005C REVERSE
SOLIDUS character (\).
7.
Unless name is geo p414 , prefix every U+003B SEMICOLON character (;) in value
with a U+005C REVERSE SOLIDUS character (\).
8.
Replace every U+000D CARRIAGE RETURN U+000A LINE FEED character pair
(CRLF) in value with a U+005C REVERSE SOLIDUS character (\) followed by a
U+006E LATIN SMALL LETTER N character (n).
9.
Replace every remaining U+000D CARRIAGE RETURN (CR) or U+000A LINE
FEED (LF) character in value with a U+005C REVERSE SOLIDUS character (\)
followed by a U+006E LATIN SMALL LETTER N character (n).
Add a vCard line p420 with the type name, the parameters parameters, and the value value to
output.
Add a vCard line p420 with the type "END" and the value "VCARD" to output.
When the above algorithm says that the user agent is to add a vCard line consisting of a type type, optionally
some parameters, and a value value to a string output, it must run the following steps:
420
1.
Let line be an empty string.
2.
Append type, converted to ASCII uppercase p33 , to line.
3.
If there are any parameters, then for each parameter, in the order that they were added, run these
substeps:
1.
Append a U+003B SEMICOLON character (;) to line.
2.
Append the parameter's name to line.
3.
Append a U+003D EQUALS SIGN character (=) to line.
4.
Append the parameter's value to line.
4.
Append a U+003A COLON character (:) to line.
5.
Append value to line.
6.
Let maximum length be 75.
7.
If and while line is longer than maximum length Unicode code points long, run the following substeps:
1.
Append the first maximum length Unicode code points of line to output.
2.
Remove the first maximum length Unicode code points from line.
3.
Append a U+000D CARRIAGE RETURN character (CR) to output.
4.
Append a U+000A LINE FEED character (LF) to output.
5.
Append a U+0020 SPACE character to output.
6.
Let maximum length be 74.
8.
Append (what remains of) line to output.
9.
Append a U+000D CARRIAGE RETURN character (CR) to output.
10.
Append a U+000A LINE FEED character (LF) to output.
When the steps above require the user agent to obtain the result of collecting vCard subproperties named
subname in subitem, the user agent must run the following steps:
1.
Let value be the empty string.
2.
For each property named subname in the item subitem, run the following substeps:
3.
1.
If the value p406 of the property is itself an item p405 , then skip this property.
2.
If this is not the first property named subname in subitem (ignoring any that were skipped by
the previous step), then append a U+002C COMMA character (,) to value.
3.
Append the result of escaping the vCard text string p421 given by the value p406 of the property
to value.
Return value.
When the steps above require the user agent to obtain the result of collecting the first vCard subproperty
named subname in subitem, the user agent must run the following steps:
1.
If there are no properties named subname in subitem, then abort these substeps, returning the empty
string.
2.
If the value p406 of the first property named subname in subitem is an item p405 , then abort these
substeps, returning the empty string.
3.
Return the result of escaping the vCard text string p421 given by the value p406 of the first property named
subname in subitem.
When the above algorithms say the user agent is to escape the vCard text string value, the user agent must
use the following steps:
1.
Prefix every U+005C REVERSE SOLIDUS character (\) in value with another U+005C REVERSE SOLIDUS
character (\).
2.
Prefix every U+002C COMMA character (,) in value with a U+005C REVERSE SOLIDUS character (\).
3.
Prefix every U+003B SEMICOLON character (;) in value with a U+005C REVERSE SOLIDUS character (\).
4.
Replace every U+000D CARRIAGE RETURN U+000A LINE FEED character pair (CRLF) in value with a
U+005C REVERSE SOLIDUS character (\) followed by a U+006E LATIN SMALL LETTER N character (n).
5.
Replace every remaining U+000D CARRIAGE RETURN (CR) or U+000A LINE FEED (LF) character in value
with a U+005C REVERSE SOLIDUS character (\) followed by a U+006E LATIN SMALL LETTER N character
(n).
6.
Return the mutated value.
Note: This algorithm can generate invalid vCard output, if the input does not conform to the
rules described for the http://microformats.org/profile/hcard p410 item type p405 and defined
property names p406 .
421
5.4.1.2 Examples
This section is non-normative.
Here is a long example vCard for a fictional character called "Jack Bauer":
Jack Bauer
Counter-Terrorist Unit
(Los Angeles Division )
10201 W. Pico Blvd. Los Angeles ,
CA
90064 United States
34.052339;-118.410623
Assorted Contact Methods
If I'm out in the field, you may be better off contacting Chloe O'Brian Tony Almeida
if you're interested in the CTU five-a-side football team we're trying to get
going.
Update!
My new home phone number is
01632 960 123 .
The odd line wrapping is needed because newlines are meaningful in microdata: newlines would be
preserved in a conversion to, for example, the vCard format.
This example shows a site's contact details (using the address p143 element) containing an address with two
street components:
Alfred
422
Person
1600 Amphitheatre Parkway Building 43, Second Floor Mountain View ,
CA 94043
The vCard vocabulary can be used to just mark up people's names:
George Washington Bluesday Tuesday: Money Road
...
May 5th @ 7pm
(until 9pm )
...
Link to this page
...
Location: The RoadHouse
...
...
.
.
.
.
Note: The subjects of the statements above are the predicates that result from converting to
RDF p431 an HTML page containing microdata with an item whose type p405 is
"http://n.whatwg.org/work p429 ".
5.4.3.2 Examples
This section is non-normative.
This example shows an embedded image entitled My Pond, licensed under the Creative Commons
Attribution-Share Alike 3.0 United States License and the MIT license simultaneously.
My Pond
Licensed under the Creative
Commons Attribution-Share Alike 3.0 United States License
and the MIT
license .
430
5.5 Converting HTML to other formats
5.5.1 JSON
Given a list of nodes nodes in a Document p31 , a user agent must run the following algorithm to extract the
microdata from those nodes into a JSON form:
1.
Let result be an empty object.
2.
Let items be an empty array.
3.
For each node in nodes, check if the element is a top-level microdata item p407 , and if it is then get the
object p431 for that element and add it to items.
4.
Add an entry to result called "items" whose value is the array items.
5.
Return the result of serializing result to JSON.
When the user agent is to get the object for an item item, it must run the following substeps:
1.
Let result be an empty object.
2.
If the item has an item type p405 , add an entry to result called "type" whose value is the item type p405 of
item.
3.
If the item has an global identifier p405 , add an entry to result called "id" whose value is the global
identifier p405 of item.
4.
Let properties be an empty object.
5.
For each element element that has one or more property names p406 and is one of the properties of the
item p407 item, in the order those elements are given by the algorithm that returns the properties of an
item p407 , run the following substeps:
1.
Let value be the property value p406 of element.
2.
If value is an item p405 , then get the object p431 for value, and then replace value with the object
returned from those steps.
3.
For each name name in element's property names p406 , run the following substeps:
1.
If there is no entry named name in properties, then add an entry named name to
properties whose value is an empty array.
2.
Append value to the entry named name in properties.
6.
Add an entry to result called "properties" whose value is the object properties.
7.
Return result.
5.5.2 RDF
To convert a Document to RDF, a user agent must run the following algorithm:
1.
If the title element p76 is not null, then generate the following triple:
subject : the document's current address p71
predicate : http://purl.org/dc/terms/title
object : the concatenation of the data of all the child text nodes p27 of the title element p76 , in tree
order p27 , as a plain literal, with the language information set from the language p85 of the title
element p76 , if it is not unknown.
2.
For each a p160 , area p266 , and link p109 element in the Document p31 , run these substeps:
1.
If the element does not have a rel attribute, then skip this element.
2.
If the element does not have an href attribute, then skip this element.
3.
If resolving p51 the element's href attribute relative to the element is not successful, then skip
this element.
431
4.
Otherwise, split the value of the element's rel attribute on spaces p49 , obtaining list of tokens.
5.
Convert each token in list of tokens that does not contain a U+003A COLON characters (:) to
ASCII lowercase p33 .
6.
If list of tokens contains more than one instance of the token up p392 , then remove all such
tokens.
7.
Coalesce duplicate tokens in list of tokens.
8.
If list of tokens contains both the tokens alternate p386 and stylesheet p391 , then remove them
both and replace them with the single (uppercase) token ALTERNATE-STYLESHEET.
9.
For each token token in list of tokens that contains no U+003A COLON characters (:), generate
the following triple:
subject : the document's current address p71
predicate : the concatenation of the string "http://www.w3.org/1999/xhtml/vocab#" and
token, with any characters in token that are not valid in the production of the
IRI syntax being %-escaped [RFC3987] p703
object : the absolute URL p52 that results from resolving p51 the value of the element's href
attribute relative to the element
For each token token in list of tokens that is an absolute URL p52 , generate the following triple:
subject : the document's current address p71
predicate : token
object : the absolute URL p52 that results from resolving p51 the value of the element's href
attribute relative to the element
3.
For each meta p112 element in the Document p31 that has a name p113 attribute and a content p113 attribute, if
the value of the name p113 attribute contains no U+003A COLON characters (:), generate the following
triple:
subject : the document's current address p71
predicate : the concatenation of the string "http://www.w3.org/1999/xhtml/vocab#" and the value
of the element's name p113 attribute, converted to ASCII lowercase p33 , with any characters in the value
that are not valid in the production of the IRI syntax being %-escaped [RFC3987] p703
object : the value of the element's content p113 attribute, as a plain literal, with the language
information set from the language p85 of the element, if it is not unknown
For each meta p112 element in the Document p31 that has a name p113 attribute and a content p113 attribute, if
the value of the name p113 attribute is an absolute URL p52 , generate the following triple:
subject : the document's current address p71
predicate : the value of the element's name p113 attribute
object : the value of the element's content p113 attribute, as a plain literal, with the language
information set from the language p85 of the element, if it is not unknown
4.
For each blockquote p151 and q p166 element in the Document p31 that has a cite attribute that resolves p51
successfully relative to the element, generate the following triple:
subject : the document's current address p71
predicate : http://purl.org/dc/terms/source
object : the absolute URL p52 that results from resolving p51 the value of the element's cite attribute
relative to the element
5.
Let memory be a mapping of items to subjects, initially empty.
6.
For each element that is also a top-level microdata item p407 , run the following steps:
1.
Generate the triples for the item p432 . Pass a reference to memory as the item/subject list. Let
result be the subject returned.
2.
Generate the following triple:
subject : the document's current address p71
predicate : http://www.w3.org/1999/xhtml/microdata#item
object : result
When the user agent is to generate the triples for an item item, given a reference to an item/subject list
memory, and optionally given a fallback type fallback type and property name fallback name, it must follow the
following steps:
432
1.
If there is an entry for item in memory, then let subject be the subject of that entry. Otherwise, if item
has a global identifier p405 and that global identifier p405 is an absolute URL p52 , let subject be that global
identifier p405 . Otherwise, let subject be a new blank node.
2.
Add a mapping from item to subject in memory, if there isn't one already.
3.
If item has an item type p405 and that item type p405 is an absolute URL p52 , let type be that item type p405 .
Otherwise, let type be the empty string.
4.
If type is not the empty string, run the following steps:
1.
Generate the following triple:
subject : subject
predicate : http://www.w3.org/1999/02/22-rdf-syntax-ns#type
object : type
5.
6.
2.
If type does not contain a U+0023 NUMBER SIGN character (#), then append a U+0023
NUMBER SIGN character (#) to type.
3.
If type does not have a U+003A COLON character (:) after its U+0023 NUMBER SIGN character
(#), append a U+003A COLON character (:) to type.
If type is the empty string, but fallback type is not, run the following substeps:
1.
Let type have the value of fallback type.
2.
If type does not contain a U+0023 NUMBER SIGN character (#), then append a U+0023
NUMBER SIGN character (#) to type.
3.
If type does not have a U+003A COLON character (:) after its U+0023 NUMBER SIGN character
(#), append a U+003A COLON character (:) to type.
4.
If the last character of type is not a U+003A COLON character (:), append a U+0025 PERCENT
SIGN character (%), a U+0032 DIGIT TWO character (2), and a U+0030 DIGIT ZERO character
(0) to type.
5.
Append the value of fallback name to type, with any characters in fallback name that are not
valid in the production of the IRI syntax being %-escaped. [RFC3987] p703
For each element element that has one or more property names p406 and is one of the properties of the
item p407 item, in the order those elements are given by the algorithm that returns the properties of an
item p407 , run the following substep:
1.
For each name name in element's property names p406 , run the following substeps:
1.
If type is the empty string and name is not an absolute URL p52 , then abort these
substeps.
2.
Let value be the property value p406 of element.
3.
If value is an item p405 , then generate the triples p432 for value. Pass a reference to
memory as the item/subject list, and pass type as the fallback type and name as the
fallback property name. Replace value by the subject returned from those steps.
4.
Otherwise, if element is not one of the URL property elements p407 , let value be a
plain literal, with the language information set from the language p85 of the element,
if it is not unknown.
5.
If name is an absolute URL p52
Let predicate be name.
If name contains no U+003A COLON characters (:)
1.
Let s be type.
2.
If the last character of s is not a U+003A COLON character (:),
append a U+0025 PERCENT SIGN character (%), a U+0032 DIGIT
TWO character (2), and a U+0030 DIGIT ZERO character (0) to s.
3.
Append the value of name to s, with any characters in name that are
not valid in the production of the IRI syntax being %escaped. [RFC3987] p703
4.
Let predicate be the concatenation of the string
"http://www.w3.org/1999/xhtml/microdata#" and s, with any
433
characters in s that are not valid in the production of
the IRI syntax being %-escaped, but without double-escaping
existing %-escapes. [RFC3987] p703
For example if the string s is "http://example.com/
a#:q%20r", the resulting predicate would be
"http://www.w3.org/1999/xhtml/
microdata#http://example.com/a%23:q%20r".
6.
Generate the following triple:
subject : subject
predicate : predicate
object : value
7.
Return subject.
5.5.2.1 Examples
This section is non-normative.
Here is an example of some HTML using Microdata to express RDF statements:
Title
Just a Geek By
Wil Wheaton Format
This is equivalent to the following Turtle:
@prefix dc: .
a frbr:Work ;
dc:creator "Wil Wheaton"@en ;
dc:title "Just a Geek"@en ;
frbr:realization ,
.
a frbr:Expression ;
dc:type .
a frbr:Expression ;
dc:type .
The following snippet of HTML has microdata for two people with the same address:
Both
Princeton Trekkie Avenue
Q .
It generates these triples expressed in Turtle (including a triple that in this case is expressed twice, though
that is not meaningful in RDF):
@prefix rdf: .
@prefix dct: .
<> _:n0 ;
_:n1 .
_:n0 rdf:type ;
hcard:fn "Princeton" ;
hcard:n _:n0a
hcard:adr _:n2 .
_:n0a hcard:n%20given-name "Princeton" .
_:n1 rdf:type ;
hcard:fn "Trekkie" ;
hcard:n _:n1a
hcard:adr _:n2 .
_:n1a hcard:n%20given-name "Trekkie" .
_:n2 hcard:adr%20street-address "Avenue Q" ;
hcard:adr%20street-address "Avenue Q" .
5.5.3 Atom
Given a Document p31 source, a user agent may run the following algorithm to extract an Atom feed. This is not
the only algorithm that can be used for this purpose; for instance, a user agent might instead use the hAtom
algorithm. [HATOM] p701
1.
If the Document p31 source does not contain any article p136 elements, then return nothing and abort
these steps. This algorithm can only be used with documents that contain distinct articles.
2.
Let R be an empty XML p71 Document p31 object whose address p71 is user-agent defined.
3.
Append a feed element in the Atom namespace p438 to R.
4.
For each meta p112 element with a name p113 attribute and a content p113 attribute and whose name p113
attribute's value is author p113 , run the following substeps:
1.
Append an author element in the Atom namespace p438 to the root element of R.
2.
Append a name element in the Atom namespace p438 to the element created in the previous
step.
3.
Append a text node whose data is the value of the meta p112 element's content p113 attribute to
the element created in the previous step.
5.
If there is a link p109 element whose rel p110 attribute's value includes the keyword icon p389 , and that
element also has an href p109 attribute whose value successfully resolves p51 relative to the link p109
element, then append an icon element in the Atom namespace p438 to the root element of R whose
contents is a text node with its data set to the absolute URL p52 resulting from resolving p51 the value of
the href p109 attribute.
6.
Append an id element in the Atom namespace p438 to the root element of R whose contents is a text
node with its data set to the document's current address p71 .
7.
Optionally: Let x be a link element in the Atom namespace p438 . Add a rel attribute whose value is the
string "self" to x. Append a text node with its data set to the (user-agent-defined) address p71 of R to x.
Append x to the root element of R.
435
Note: This step would be skipped when the document R has no convenient address p71 .
The presence of the rel="self" link is a "should"-level requirement in the Atom
specification.
8.
Let x be a link element in the Atom namespace p438 . Add a rel attribute whose value is the string
"alternate" to x. If the document being converted is an HTML document p71 , add a type attribute whose
value is the string "text/html p678 " to x. Otherwise, the document being converted is an XML
document p71 ; add a type attribute whose value is the string "application/xhtml+xml p680 " to x. Append
a text node with its data set to the document's current address p71 to x. Append x to the root element of
R.
9.
Let subheading text be the empty string.
10.
Let heading be the first element of heading content p91 whose nearest ancestor of sectioning content p91
is the body element p76 , if any, or null if there is none.
11.
Take the appropriate action from the following list, as determined by the type of the heading element:
If heading is null
Let heading text be the textContent p31 of the title element p76 , if there is one, or the empty
string otherwise.
If heading is a hgroup p140 element
If heading contains no child h1 p139 –h6 p139 elements, let heading text be the empty string.
Otherwise, let headings list be a list of all the h1 p139 –h6 p139 element children of heading, sorted first
by descending rank p139 and then in tree order p27 (so h1 p139 s first, then h2 p139 s, etc, with each group
in the order they appear in the document). Then, let heading text be the textContent p31 of the
first entry in headings list, and if there are multiple entries, let subheading text be the
textContent p31 of the second entry in headings list.
If heading is an h1 p139 –h6 p139 element
Let heading text be the textContent p31 of heading.
12.
Append a title element in the Atom namespace p438 to the root element of R whose contents is a text
node with its data set to heading text.
13.
If subheading text is not the empty string, append a subtitle element in the Atom namespace p438 to
the root element of R whose contents is a text node with its data set to subheading text.
14.
Let global update date have no value.
15.
For each article p136 element article that does not have an ancestor article p136 element, run the
following steps:
1.
Let E be an entry element in the Atom namespace p438 , and append E to the root element of R.
2.
Let heading be the first element of heading content p91 whose nearest ancestor of sectioning
content p91 is article, if any, or null if there is none.
3.
Take the appropriate action from the following list, as determined by the type of the heading
element:
If heading is null
Let heading text be the empty string.
If heading is a hgroup p140 element
If heading contains no child h1 p139 –h6 p139 elements, let heading text be the empty string.
Otherwise, let headings list be a list of all the h1 p139 –h6 p139 element children of heading,
sorted first by descending rank p139 and then in tree order p27 (so h1 p139 s first, then h2 p139 s,
etc, with each group in the order they appear in the document). Then, let heading text
be the textContent p31 of the first entry in headings list.
If heading is an h1 p139 –h6 p139 element
Let heading text be the textContent p31 of heading.
4.
436
Append a title element in the Atom namespace p438 to E whose contents is a text node with
its data set to heading text.
5.
Clone article and its descendants into an environment that has scripting disabled p487 , has no
plugins p27 , and fails any attempt to fetch p55 any resources. Let cloned article be the resulting
clone article p136 element.
6.
Remove from the subtree rooted at cloned article any article p136 elements other than the
cloned article itself, any header p140 , footer p142 , or nav p134 elements whose nearest ancestor of
sectioning content p91 is the cloned article, and the first element of heading content p91 whose
nearest ancestor of sectioning content p91 is the cloned article, if any.
7.
If cloned article contains any ins p182 or del p183 elements with datetime p184 attributes whose
values parse as global date and time strings p44 without errors, then let update date be the
value of the datetime p184 attribute that parses to the newest global date and time p44 .
Otherwise, let update date have no value.
Note: This value is used below; it is calculated here because in certain cases
the next step mutates the cloned article.
8.
If the document being converted is an HTML document p71 , then: Let x be a content element in
the Atom namespace p438 . Add a type attribute whose value is the string "html" to x. Append a
text node with its data set to the result of running the HTML fragment serialization
algorithm p625 on cloned article to x. Append x to E.
Otherwise, the document being converted is an XML document p71 : Let x be a content element
in the Atom namespace p438 . Add a type attribute whose value is the string "xml" to x. Append
a div p159 element to x. Move all the child nodes of the cloned article node to that div p159
element, preserving their relative order. Append x to E.
9.
Establish the value of id and has-alternate from the first of the following to apply:
If the article node has a descendant a p160 or area p266 element with an href p383
attribute that successfully resolves p51 relative to that descendant and a rel
attribute whose value includes the bookmark p388 keyword
Let id be the absolute URL p52 resulting from resolving p51 the value of the href p383
attribute of the first such a p160 or area p266 element, relative to the element. Let hasalternate be true.
If the article node has an id p84 attribute
Let id be the document's current address p71 , with the fragment identifier (if any)
removed, and with a new fragment identifier specified, consisting of the value of the
article element's id p84 attribute. Let has-alternate be false.
Otherwise
Let id be a user-agent-defined undereferenceable yet globally unique valid p51 absolute
URL p52 . The same absolute URL p52 should be generated for each run of this algorithm
when given the same input. Let has-alternate be false.
10.
Append an id element in the Atom namespace p438 to E whose contents is a text node with its
data set to id.
11.
If has-alternate is true: Let x be a link element in the Atom namespace p438 . Add a rel
attribute whose value is the string "alternate" to x. Append a text node with its data set to id
to x. Append x to E.
12.
If article has a time p168 element descendant that has a pubdate p169 attribute and whose
nearest ancestor article p136 element is article, and the first such element's date p170 is not
unknown, then run the following substeps, with e being the first such element:
1.
Let datetime be a global date and time p44 whose date component is the date p170 of
e.
2.
If e's time p170 and time-zone offset p170 are not unknown, then let datetime's time and
time-zone offset components be the time p170 and time-zone offset p170 of e.
Otherwise, let them be midnight and no offset respectively ("00:00Z").
3.
Let publication date be the best representation of the global date and time string p44
datetime.
Otherwise, let publication date have no value.
13.
If update date has no value but publication date does, then let update date have the value of
publication date.
437
Otherwise, if publication date has no value but update date does, then let publication date
have the value of update date.
14.
If update date has a value, and global update date has no value or is less recent than update
date, then let global update date have the value of update date.
15.
If publication date and update date both still have no value, then let them both value a value
that is a valid global date and time string p44 representing the global date and time p44 of the
moment that this algorithm was invoked.
16.
Append an published element in the Atom namespace p438 to E whose contents is a text node
with its data set to publication date.
17.
Append an updated element in the Atom namespace p438 to E whose contents is a text node
with its data set to update date.
16.
If global update date has no value, then let it have a value that is a valid global date and time string p44
representing the global date and time p44 of the date and time of the Document p31 's source file's last
modification, if it is known, or else of the moment that this algorithm was invoked.
17.
Insert an updated element in the Atom namespace p438 into the root element of R before the first entry
in the Atom namespace p438 whose contents is a text node with its data set to global update date.
18.
Return the Atom document R.
Note: The above algorithm does not guarantee that the output will be a conforming Atom
feed. In particular, if insufficient information is provided in the document (e.g. if the document
does not have any p51 component of url, converted to ASCII lowercase p33 .
449
6.
If the UA doesn't support the protocol given by scheme, then return a new globally unique
identifier.
7.
If scheme is "file", then the user agent may return a UA-specific value.
8.
Let host be the p51 component of url.
9.
Apply the IDNA ToASCII algorithm to host, with both the AllowUnassigned and UseSTD3ASCIIRules
flags set. Let host be the result of the ToASCII algorithm.
If ToASCII fails to convert one of the components of the string, e.g. because it is too long or
because it contains invalid characters, then return a new globally unique identifier. [RFC3490] p703
10.
Let host be the result of converting host to ASCII lowercase p33 .
11.
If there is no p51 component, then let port be the default port for the protocol given by
scheme. Otherwise, let port be the p51 component of url.
12.
Return the tuple (scheme, host, port).
In addition, if the URL p51 is in fact associated with a Document p31 object that was created by parsing the
resource obtained from fetching URL p51 , and this was done over a secure connection, then the server's
secure certificate may be added to the origin as additional data.
For scripts
The origin p449 and effective script origin p449 of a script are determined from another resource, called the
owner:
p122
element
↪ If a script is in a script
The owner is the Document p31 to which the script p122 element belongs.
p492
↪ If a script is in an event handler content attribute
p31
The owner is the Document
to which the attribute node belongs.
↪ If a script is a function or other code reference created by another script
The owner is the script that created it.
p491
that was returned as the location of an HTTP redirect (or
↪ If a script is a javascript: URL
p56
equivalent
in other protocols)
The owner is the URL p51 that redirected to the javascript: URL p491 .
p491
in an attribute
↪ If a script is a javascript: URL
p31
The owner is the Document
of the element on which the attribute is found.
p491
in a style sheet
↪ If a script is a javascript: URL
p51
The owner is the URL
of the style sheet.
p491
to which a browsing context p439 is being navigated p459 , the
↪ If a script is a javascript: URL
URL having been provided by the user (e.g. by using a bookmarklet)
The owner is the Document p31 of the browsing context p439 's active document p439 .
p491
to which a browsing context p439 is being navigated p459 , the
↪ If a script is a javascript: URL
URL having been declared in markup
The owner is the Document p31 of the element (e.g. an a p160 or area p266 element) that declared the
URL.
p491
to which a browsing context p439 is being navigated p459 , the
↪ If a script is a javascript: URL
URL having been provided by script
The owner is the script that provided the URL.
The origin p449 of the script is then equal to the origin p449 of the owner, and the effective script origin p449 of
the script is equal to the effective script origin p449 of the owner.
For Document p31 objects and images
p31
is in a browsing context p439 whose sandboxed origin browsing context flag p203
↪ If a Document
was set when the Document p31 was created
p31
was generated from a resource labeled as text/html-sandboxed p679
↪ If a Document
p449
The origin
is a globally unique identifier assigned when the Document p31 is created.
p31
or image was returned by the XMLHttpRequest API
↪ If a Document
The origin p449 is equal to the XMLHttpRequest origin of the XMLHttpRequest object. [XHR] p705
p31
or image was generated from a javascript: URL p491
↪ If a Document
p449
The origin
is equal to the origin p449 of the script of that javascript: URL p491 .
p31
or image was served over the network and has an address that uses a URL
↪ If a Document
scheme with a server-based naming authority
The origin p449 is the origin p449 of the address p71 of the Document p31 or the URL p51 of the image, as
appropriate.
450
p31
or image was generated from a data: URL that was returned as the location of
↪ If a Document
an HTTP redirect (or equivalent p56 in other protocols)
The origin p449 is the origin p449 of the URL p51 that redirected to the data: URL.
p31
or image was generated from a data: URL found in another Document p31 or in a
↪ If a Document
script
The origin p449 is the origin p449 of the Document p31 or script that initiated the navigation p459 to that
URL p51 .
p31
has the address p71 "about:blank p56 "
↪ If a Document
p449
The origin
of the Document p31 is the origin it was assigned when its browsing context was
p439
created
.
p31
is an iframe srcdoc document p200
↪ If a Document
p449
The origin
of the Document p31 is the origin p449 of the Document p31 's browsing context p439 's
browsing context container p439 's Document p31 .
p31
or image was obtained in some other manner (e.g. a data: URL typed in by
↪ If a Document
the user, a Document p31 created using the createDocument() p31 API, etc)
The origin p449 is a globally unique identifier assigned when the Document p31 or image is created.
When a Document p31 is created, its effective script origin p449 is initialized to the origin p449 of the Document p31 .
However, the document.domain p452 attribute can be used to change it.
For audio p216 and video p213 elements
If value of the media element p219 's currentSrc p220 attribute is the empty string, the origin p449 is the same as
the origin p449 of the element's Document p31 's origin p449 .
Otherwise, the origin p449 is equal to the origin p449 of the absolute URL p52 given by the media element p219 's
currentSrc p220 attribute.
The Unicode serialization of an origin is the string obtained by applying the following algorithm to the given
origin p449 :
1.
If the origin p449 in question is not a scheme/host/port tuple, then return the literal string "null" and abort
these steps.
2.
Otherwise, let result be the scheme part of the origin p449 tuple.
3.
Append the string "://" to result.
4.
Apply the IDNA ToUnicode algorithm to each component of the host part of the origin p449 tuple, and
append the results — each component, in the same order, separated by U+002E FULL STOP characters
(.) — to result. [RFC3490] p703
5.
If the port part of the origin p449 tuple gives a port that is different from the default port for the protocol
given by the scheme part of the origin p449 tuple, then append a U+003A COLON character (:) and the
given port, in base ten, to result.
6.
Return result.
The ASCII serialization of an origin is the string obtained by applying the following algorithm to the given
origin p449 :
1.
If the origin p449 in question is not a scheme/host/port tuple, then return the literal string "null" and abort
these steps.
2.
Otherwise, let result be the scheme part of the origin p449 tuple.
3.
Append the string "://" to result.
4.
Apply the IDNA ToASCII algorithm the host part of the origin p449 tuple, with both the AllowUnassigned and
UseSTD3ASCIIRules flags set, and append the results result.
If ToASCII fails to convert one of the components of the string, e.g. because it is too long or because it
contains invalid characters, then return the empty string and abort these steps. [RFC3490] p703
5.
If the port part of the origin p449 tuple gives a port that is different from the default port for the protocol
given by the scheme part of the origin p449 tuple, then append a U+003A COLON character (:) and the
given port, in base ten, to result.
6.
Return result.
Two origins p449 are said to be the same origin if the following algorithm returns true:
1.
Let A be the first origin p449 being compared, and B be the second origin p449 being compared.
451
2.
If A and B are both opaque identifiers, and their value is equal, then return true.
3.
Otherwise, if either A or B or both are opaque identifiers, return false.
4.
If A and B have scheme components that are not identical, return false.
5.
If A and B have host components that are not identical, return false.
6.
If A and B have port components that are not identical, return false.
7.
If either A or B have additional data, but that data is not identical for both, return false.
8.
Return true.
6.3.1 Relaxing the same-origin restriction
This box is non-normative. Implementation requirements are given below this box.
document . domain
p452
[ = domain ]
Returns the current domain used for security checks.
Can be set to a value that removes subdomains, to change the effective script origin p449 to allow
pages on other subdomains of the same domain (if they do the same thing) to access each other.
The domain attribute on Document p31 objects must be initialized to the document's domain p452 , if it has one, and
the empty string otherwise. If the value is an IPv6 address, then the square brackets from the host portion of the
p51 component must be omitted from the attribute's value.
On getting, the attribute must return its current value, unless the document was created by XMLHttpRequest, in
which case it must throw an INVALID_ACCESS_ERR p70 exception.
On setting, the user agent must run the following algorithm:
1.
If the document was created by XMLHttpRequest, throw an INVALID_ACCESS_ERR p70 exception and abort
these steps.
2.
If the new value is an IP address, let new value be the new value. Otherwise, apply the IDNA ToASCII
algorithm to the new value, with both the AllowUnassigned and UseSTD3ASCIIRules flags set, and let
new value be the result of the ToASCII algorithm.
If ToASCII fails to convert one of the components of the string, e.g. because it is too long or because it
contains invalid characters, then throw a SECURITY_ERR p70 exception and abort these steps.
[RFC3490] p703
3.
If new value is not exactly equal to the current value of the document.domain p452 attribute, then run
these substeps:
1.
If the current value is an IP address, throw a SECURITY_ERR p70 exception and abort these steps.
2.
If new value, prefixed by a U+002E FULL STOP (.), does not exactly match the end of the
current value, throw a SECURITY_ERR p70 exception and abort these steps.
3.
If new value matches a suffix in the Public Suffix List, or, if new value, prefixed by a U+002E
FULL STOP (.), matches the end of a suffix in the Public Suffix List, then throw a
SECURITY_ERR p70 exception and abort these steps. [PSL] p702
Suffixes must be compared after applying the IDNA ToASCII algorithm to them, with both the
AllowUnassigned and UseSTD3ASCIIRules flags set, in an ASCII case-insensitive p33 manner.
[RFC3490] p703
4.
Release the storage mutex p490 .
5.
Set the attribute's value to new value.
6.
Set the host part of the effective script origin p449 tuple of the Document p31 to new value.
7.
Set the port part of the effective script origin p449 tuple of the Document p31 to "manual override" (a value
that, for the purposes of comparing origins p451 , is identical to "manual override" but not identical to any
other value).
The domain of a Document p31 is the host part of the document's origin p449 , if that is a scheme/host/port tuple. If it
isn't, then the document does not have a domain.
452
Note: The domain p452 attribute is used to enable pages on different hosts of a domain to access
each others' DOMs.
⚠Warning! Do not use the document.domain p452 attribute when using shared hosting. If an untrusted
third party is able to host an HTTP server at the same IP address but on a different port, then the
same-origin protection that normally protects two different sites on the same host will fail, as the
ports are ignored when comparing origins after the document.domain p452 attribute has been used.
6.4 Session history and navigation
6.4.1 The session history of browsing contexts
The sequence of Document p31 s in a browsing context p439 is its session history.
History p454 objects provide a representation of the pages in the session history of browsing contexts p439 . Each
browsing context p439 , including nested browsing contexts p439 , has a distinct session history.
Each Document p31 object in a browsing context p439 's session history p453 is associated with a unique instance of the
History p454 object, although they all must model the same underlying session history p453 .
The history attribute of the Window p443 interface must return the object implementing the History p454 interface
for that Window p443 object's Document p31 .
History p454 objects represent their browsing context p439 's session history as a flat list of session history entries p453 .
Each session history entry consists of either a URL p51 or a state object p453 , or both, and may in addition have a
title, a Document p31 object, form data, a scroll position, and other information associated with it.
Note: This does not imply that the user interface need be linear. See the notes below p458 .
Note: Titles associated with session history entries p453 need not have any relation with the
current title p107 of the Document p31 . The title of a session history entry p453 is intended to
explain the state of the document at that point, so that the user can navigate the document's
history.
URLs without associated state objects p453 are added to the session history as the user (or script) navigates from
page to page.
A state object is an object representing a user interface state.
Pages can add p455 state objects p453 between their entry in the session history and the next ("forward") entry. These
are then returned to the script p467 when the user (or script) goes back in the history, thus enabling authors to use
the "navigation" metaphor even in one-page applications.
At any point, one of the entries in the session history is the current entry. This is the entry representing the
active document p439 of the browsing context p439 . The current entry p453 is usually an entry for the location p458 of the
Document p31 . However, it can also be one of the entries for state objects p453 added to the history by that
document.
Entries that consist of state objects p453 share the same Document p31 as the entry for the page that was active when
they were added.
Contiguous entries that differ just by fragment identifier also share the same Document p31 .
Note: All entries that share the same Document p31 (and that are therefore merely different
states of one particular document) are contiguous by definition.
User agents may discard p447 the Document p31 objects of entries other than the current entry p453 that are not
referenced from any script, reloading the pages afresh when the user or script navigates back to such pages. This
specification does not specify when user agents should discard Document p31 objects and when they should cache
them.
Entries that have had their Document p31 objects discarded must, for the purposes of the algorithms given below,
act as if they had not. When the user or script navigates back or forwards to a page which has no in-memory DOM
objects, any other entries that shared the same Document p31 object with it must share the new object as well.
453
6.4.2 The History p454 interface
interface History {
readonly attribute long length;
void go(in optional long delta);
void back();
void forward();
void pushState(in any data, in DOMString title, in optional DOMString url);
void replaceState(in any data, in DOMString title, in optional DOMString url);
};
This box is non-normative. Implementation requirements are given below this box.
window . history
p453
. length p454
Returns the number of entries in the joint session history p454 .
window . history p453 . go p454 ( [ delta ] )
Goes back or forward the specified number of steps in the joint session history p454 .
A zero delta will reload the current page.
If the delta is out of range, does nothing.
window . history p453 . back p454 ()
Goes back one step in the joint session history p454 .
If there is no previous page, does nothing.
window . history p453 . forward p454 ()
Goes forward one step in the joint session history p454 .
If there is no next page, does nothing.
window . history p453 . pushState p455 (data, title [, url ] )
Pushes the given data onto the session history, with the given title, and, if provided, the given URL.
window . history p453 . replaceState p455 (data, title [, url ] )
Updates the current entry in the session histor to have the given data, title, and, if provided, URL.
The joint session history of a History p454 object is the union of all the session histories p453 of all browsing
contexts p439 of all the fully active p440 Document p31 objects that share the History p454 object's top-level browsing
context p439 , with all the entries that are current entries p453 in their respective session histories p453 removed except
for the current entry of the joint session history p454 .
The current entry of the joint session history is the entry that most recently became a current entry p453 in its
session history p453 .
Entries in the joint session history p454 are ordered chronologically by the time they were added to their respective
session histories p453 . (Since all these browsing contexts p439 by definition share an event loop p489 , there is always a
well-defined sequential order in which their session histories p453 had their entries added.) Each entry has an index;
the earliest entry has index 0, and the subsequent entries are numbered with consecutively increasing integers (1,
2, 3, etc).
The length attribute of the History p454 interface must return the number of entries in the joint session history p454 .
The actual entries are not accessible from script.
When the go(delta) method is invoked, if the argument to the method was omitted or has the value zero, the
user agent must act as if the location.reload() p458 method was called instead. Otherwise, the user agent must
traverse the history by a delta p454 whose value is the value of the method's argument.
When the back() method is invoked, the user agent must traverse the history by a delta p454 −1.
When the forward()method is invoked, the user agent must traverse the history by a delta p454 +1.
To traverse the history by a delta delta, the user agent must queue a task p490 to run the following steps. The
task source p490 for the queued task is the history traversal task source p491 .
1.
454
Let delta be the argument to the method.
2.
If the index of the current entry of the joint session history p454 plus delta is less than zero or greater than
or equal to the number of items in the joint session history p454 , then the user agent must do nothing.
3.
Let specified entry be the entry in the joint session history p454 whose index is the sum of delta and the
index of the current entry of the joint session history p454 .
4.
Let specified browsing context be the browsing context p439 of the specified entry.
5.
Traverse the history p465 of the specified browsing context to the specified entry.
When the user navigates through a browsing context p439 , e.g. using a browser's back and forward buttons, the
user agent must traverse the history by a delta p454 equivalent to the action specified by the user.
The pushState(data, title, url) method adds a state object entry to the history.
The replaceState(data, title, url) method updates the state object, title, and optionally the URL p51 of the
current entry p453 in the history.
When either of these methods is invoked, the user agent must run the following steps:
1.
Let clone data be a structured clone p67 of the specified data. If this throws an exception, then rethrow
that exception and abort these steps.
2.
If a third argument is specified, run these substeps:
1.
Resolve p51 the value of the third argument, relative to the entry script p441 's base URL p488 .
2.
If that fails, raise a SECURITY_ERR p70 exception and abort these steps.
3.
Compare the resulting absolute URL p52 to the document's address p71 . If any part of these two
URLs p51 differ other than the p51 , p51 , and p51 components, then
raise a SECURITY_ERR p70 exception and abort these steps.
4.
If the origin p449 of the resulting absolute URL p52 is not the same as the origin p449 of the entry
script p441 's document p488 , and either the p51 or p51 components of the two
URLs p51 compared in the previous step differ, raise a SECURITY_ERR p70 exception and abort
these steps. (This prevents sandboxed content from spoofing other pages on the same origin.)
For the purposes of the comparisons in the above substeps, the p51 and p51 components
can only be the same if the URLs are both hierarchical URLs p52 .
3.
If the method invoked was the pushState() p455 method:
1.
Remove all the entries in the browsing context p439 's session history p453 after the current
entry p453 . If the current entry p453 is the last entry in the session history, then no entries are
removed.
Note: This doesn't necessarily have to affect p458 the user agent's user
interface.
2.
Remove any tasks p489 queued by the history traversal task source p491 .
3.
Add a state object entry to the session history, after the current entry p453 , with cloned data as
the state object, the given title as the title, and, if the third argument is present, the absolute
URL p52 that was found earlier in this algorithm as the URL p51 of the entry.
4.
Update the current entry p453 to be the this newly added entry.
Otherwise, if the method invoked was the replaceState() p455 method:
1.
4.
Update the current entry p453 in the session history so that cloned data is the entry's new state
object, the given title is the new title, and, if the third argument is present, the absolute URL p52
that was found earlier in this algorithm is the entry's new URL p51 .
If the third argument is present, set the document's current address p71 to the absolute URL p52 that was
found earlier in this algorithm.
Note: Since this is neither a navigation p459 of the browsing context p439 nor a history
traversal p465 , it does not cause a hashchange p467 event to be fired.
Note: The title is purely advisory. User agents might use the title in the user interface.
455
User agents may limit the number of state objects added to the session history per page. If a page hits the UAdefined limit, user agents must remove the entry immediately after the first entry for that Document p31 object in
the session history after having added the new entry. (Thus the state history acts as a FIFO buffer for eviction, but
as a LIFO buffer for navigation.)
Consider a game where the user can navigate along a line, such that the user is always at some coordinate,
and such that the user can bookmark the page corresponding to a particular coordinate, to return to it later.
A static page implementing the x=5 position in such a game could look like the following:
Line Game - 5
You are at coordinate 5 on the line.
Advance to 6 or
retreat to 4 ?
The problem with such a system is that each time the user clicks, the whole page has to be reloaded. Here
instead is another way of doing it, using script:
Line Game - 5
You are at coordinate 5 on the line.
Advance to 6 or
retreat to 4 ?
In systems without script, this still works like the previous example. However, users that do have script
support can now navigate much faster, since there is no network access for the same experience.
Furthermore, contrary to the experience the user would have with just a naïve script-based approach,
bookmarking and navigating the session history still work.
In the example above, the data argument to the pushState() p455 method is the same information as would
be sent to the server, but in a more convenient form, so that the script doesn't have to parse the URL each
time the user navigates.
Applications might not use the same title for a session history entry p453 as the value of the document's
title p107 element at that time. For example, here is a simple page that shows a block in the title p107
element. Clearly, when navigating backwards to a previous state the user does not go back in time, and
therefore it would be inappropriate to put the time in the session history title.
Line
6.4.3 The Location p457 interface
Each Document p31 object in a browsing context p439 's session history is associated with a unique instance of a
Location p457 object.
This box is non-normative. Implementation requirements are given below this box.
document . location
p457
[ = value ]
window . location p457 [ = value ]
Returns a Location p457 object with the current page's location.
Can be set, to navigate to another page.
The location attribute of the HTMLDocument p71 interface must return the Location p457 object for that Document p31
object, if it is in a browsing context p439 , and null otherwise.
The location attribute of the Window p443 interface must return the Location p457 object for that Window p443 object's
Document p31 .
Location p457 objects provide a representation of their document's current address p71 , and allow the current
entry p453 of the browsing context p439 's session history to be changed, by adding or replacing entries in the
history p453 object.
interface Location {
stringifier attribute DOMString href;
void assign(in DOMString url);
void replace(in DOMString url);
void reload();
// URL decomposition IDL attributes
attribute DOMString protocol;
attribute DOMString host;
attribute DOMString hostname;
attribute DOMString port;
attribute DOMString pathname;
attribute DOMString search;
attribute DOMString hash;
// resolving relative URLs
DOMString resolveURL(in DOMString url);
};
This box is non-normative. Implementation requirements are given below this box.
location . href
p458
[ = value ]
Returns the current page's location.
Can be set, to navigate to another page.
location . assign p458 (url)
Navigates to the given page.
location . replace p458 (url)
Removes the current page from the session history and navigates to the given page.
457
location . reload p458 ()
Reloads the current page.
url = location . resolveURL p458 (url)
Resolves the given relative URL to an absolute URL.
The href attribute must return the current address p71 of the associated Document p31 object, as an absolute URL p52 .
On setting, the user agent must act as if the assign() p458 method had been called with the new value as its
argument.
When the assign(url) method is invoked, the UA must resolve p51 the argument, relative to the entry script p441 's
base URL p488 , and if that is successful, must navigate p459 the browsing context p439 to the specified url. If the
browsing context p439 's session history p453 contains only one Document p31 , and that was the about:blank p56
Document p31 created when the browsing context p439 was created, then the navigation must be done with
replacement enabled p466 .
When the replace(url) method is invoked, the UA must resolve p51 the argument, relative to the entry script p441 's
base URL p488 , and if that is successful, navigate p459 the browsing context p439 to the specified url with replacement
enabled p466 .
Navigation for the assign() p458 and replace() p458 methods must be done with the browsing context p488 of the
script that invoked the method as the source browsing context p459 .
If the resolving p51 step of the assign() p458 and replace() p458 methods is not successful, then the user agent must
instead throw a SYNTAX_ERR p70 exception.
When the reload() method is invoked, the user agent must run the appropriate steps from the following list:
p489
is the dispatch of a resize event in response to the user
↪ If the currently executing task
p439
resizing the browsing context
Repaint the browsing context p439 and abort these steps.
↪ Otherwise
Navigate p459 the browsing context p439 to the document's current address p71 with replacement
enabled p466 . The source browsing context p459 must be the browsing context p439 being navigated.
When a user requests that the current page be reloaded through a user interface element, the user agent should
navigate p459 the browsing context p439 to the same resource as Document p31 , with replacement enabled p466 . In the
case of non-idempotent methods (e.g. HTTP POST), the user agent should prompt the user to confirm the
operation first, since otherwise transactions (e.g. purchases or database modifications) could be repeated. User
agents may allow the user to explicitly override any caches when reloading.
The Location p457 interface also has the complement of URL decomposition IDL attributes p53 , protocol, host,
port, hostname, pathname, search, and hash. These must follow the rules given for URL decomposition IDL
attributes, with the input p54 being the current address p71 of the associated Document p31 object, as an absolute
URL p52 (same as the href p458 attribute), and the common setter action p54 being the same as setting the href p458
attribute to the new output value.
The resolveURL(url) method must resolve p51 its url argument, relative to the entry script p441 's base URL p488 , and
if that succeeds, return the resulting absolute URL p52 . If it fails, it must throw a SYNTAX_ERR p70 exception instead.
6.4.3.1 Security
User agents must raise a SECURITY_ERR p70 exception whenever any of the members of a Location p457 object are
accessed by scripts whose effective script origin p449 is not the same p451 as the Location p457 object's associated
Document p31 's effective script origin p449 , with the following exceptions:
•
The href p458 setter, if the script is running in a browsing context p439 that is allowed to navigate p441 the
browsing context with which the Location p457 object is associated
•
The replace() p458 method, if the script is running in a browsing context p439 that is allowed to
navigate p441 the browsing context with which the Location p457 object is associated
6.4.4 Implementation notes for session history
This section is non-normative.
458
The History p454 interface is not meant to place restrictions on how implementations represent the session history
to the user.
For example, session history could be implemented in a tree-like manner, with each page having multiple
"forward" pages. This specification doesn't define how the linear list of pages in the history p453 object are derived
from the actual session history as seen from the user's perspective.
Similarly, a page containing two iframe p199 s has a history p453 object distinct from the iframe p199 s' history p453
objects, despite the fact that typical Web browsers present the user with just one "Back" button, with a session
history that interleaves the navigation of the two inner frames and the outer page.
Security: It is suggested that to avoid letting a page "hijack" the history navigation facilities of a UA by abusing
pushState() p455 , the UA provide the user with a way to jump back to the previous page (rather than just going
back to the previous state). For example, the back button could have a drop down showing just the pages in the
session history, and not showing any of the states. Similarly, an aural browser could have two "back" commands,
one that goes back to the previous state, and one that jumps straight back to the previous page.
In addition, a user agent could ignore calls to pushState() p455 that are invoked on a timer, or from event listeners
that are not triggered in response to a clear user action, or that are invoked in rapid succession.
6.5 Browsing the Web
6.5.1 Navigating across documents
Certain actions cause the browsing context p439 to navigate p459 to a new resource. Navigation always involves
source browsing context, which is the browsing context which was responsible for starting the navigation.
For example, following a hyperlink p384 , form submission p361 , and the window.open() p445 and
location.assign() p458 methods can all cause a browsing context to navigate.
A user agent may provide various ways for the user to explicitly cause a browsing context to navigate, in addition
to those defined in this specification.
When a browsing context is navigated to a new resource, the user agent must run the following steps:
1.
Release the storage mutex p490 .
2.
If the source browsing context p459 is not the same as the browsing context p439 being navigated, and the
source browsing context p459 is not one of the ancestor browsing contexts p440 of the browsing context p439
being navigated, and the browsing context p439 being navigated is not both a top-level browsing
context p439 and one of the ancestor browsing contexts p440 of the source browsing context p459 , and the
source browsing context p459 had its sandboxed navigation browsing context flag p202 set when its active
document p439 was created, then abort these steps.
Otherwise, if the browsing context p439 being navigated is a top-level browsing context p439 , and is one of
the ancestor browsing contexts p440 of the source browsing context p459 , and the source browsing
context p459 had its sandboxed top-level navigation browsing context flag p202 set when its active
document p439 was created, then abort these steps.
In both cases, the user agent may additionally offer to open the new resource in a new top-level
browsing context p439 or in the top-level browsing context p439 of the source browsing context p459 , at the
user's option, in which case the user agent must navigate p459 that designated top-level browsing
context p439 to the new resource as if the user had requested it independently.
3.
If the source browsing context p459 is the same as the browsing context p439 being navigated, and this
browsing context has its seamless browsing context flag p204 set, then find the nearest ancestor browsing
context p440 that does not have its seamless browsing context flag p204 set, and continue these steps as if
that browsing context p439 was the one that was going to be navigated p459 instead.
4.
If there is a preexisting attempt to navigate the browsing context p439 , and the source browsing
context p459 is the same as the browsing context p439 being navigated, and that attempt is currently
running the unload a document p469 algorithm, and the origin p449 of the URL p51 of the resource being
loaded in that navigation is not the same origin p451 as the origin p449 of the URL p51 of the resource being
loaded in this navigation, then abort these steps without affecting the preexisting attempt to navigate
the browsing context p439 .
5.
If there is a preexisting attempt to navigate the browsing context p439 , and either that attempt has not
yet matured p462 (i.e. it has not passed the point of making its Document p31 the active document p439 ), or
that navigation's resource is not to be fetched using HTTP GET or equivalent p56 , or its resource's
459
absolute URL p52 differs from this attempt's by more than the presence, absence, or value of the
p51 component, then cancel that preexisting attempt to navigate the browsing context p439 .
6.
Fragment identifiers: If the absolute URL p52 of the new resource is the same as the address p71 of the
active document p439 of the browsing context p439 being navigated, ignoring any p51
components of those URLs p51 , and the new resource is to be fetched using HTTP GET or equivalent p56 ,
and the absolute URL p52 of the new resource has a p51 component (even if it is empty), then
navigate to that fragment identifier p465 and abort these steps.
7.
Cancel any preexisting attempt to navigate the browsing context p439 .
8.
If the new resource is to be handled using a mechanism that does not affect the browsing context, e.g.
ignoring the navigation request altogether because the specified scheme is not one of the supported
protocols, then abort these steps and proceed with that mechanism instead.
9.
Prompt to unload p468 the Document p31 object. If the user refused to allow the document to be
unloaded p468 , then these steps must be aborted.
10.
If the new resource is to be handled by displaying some sort of inline content, e.g. an error message
because the specified scheme is not one of the supported protocols, or an inline prompt to allow the
user to select a registered handler p503 for the given scheme, then display the inline content p464 and abort
these steps.
Note: In the case of a registered handler being used, the algorithm will be reinvoked
with a new URL to handle the request.
11.
If the new resource is to be fetched using HTTP GET or equivalent p56 , then check if there are any
relevant application caches p472 that are identified by a URL with the same origin p451 as the URL in
question, and that have this URL as one of their entries, excluding entries marked as foreign p471 . If so,
then the user agent must then get the resource from the most appropriate application cache p472 of those
that match.
For example, imagine an HTML page with an associated application cache displaying an image
and a form, where the image is also used by several other application caches. If the user rightclicks on the image and chooses "View Image", then the user agent could decide to show the
image from any of those caches, but it is likely that the most useful cache for the user would be
the one that was used for the aforementioned HTML page. On the other hand, if the user submits
the form, and the form does a POST submission, then the user agent will not use an application
cache at all; the submission will be made to the network.
Otherwise, unless it has already been obtained, fetch p55 the new resource, with the manual redirect flag
set.
If the resource is being fetched using a method other than one equivalent to p56 HTTP's GET, or, if the
navigation algorithm p459 was invoked as a result of the form submission algorithm p361 , then the fetching
algorithm p55 must be invoked from the origin p449 of the active document p439 of the source browsing
context p459 , if any.
If the browsing context p439 being navigated is a child browsing context p439 for an iframe p199 or object p208
element, then the fetching algorithm p55 must be invoked from the iframe p199 or object p208 element's
browsing context scope origin p441 , if it has one.
12.
At this point, unless this step has already been reached once before in the execution of this instance of
the algorithm, the user agents must return to whatever algorithm invoked the navigation steps and must
continue these steps asynchronously.
13.
If fetching the resource results in a redirect, and either the URL p51 of the target of the redirect has the
same origin p451 as the original resource, or the resource is being obtained using the POST method or a
safe method (in HTTP terms), return to the step labeled "fragment identifiers" p460 with the new resource.
Otherwise, if fetching the resource results in a redirect but the URL p51 of the target of the redirect does
not have the same origin p451 as the original resource and the resource is being obtained using a method
that is neither the POST method nor a safe method (in HTTP terms), then abort these steps. The user
agent may indicate to the user that the navigation has been aborted for security reasons.
460
14.
Wait for one or more bytes to be available or for the user agent to establish that the resource in question
is empty. During this time, the user agent may allow the user to cancel this navigation attempt or start
other navigation attempts.
15.
If the resource was not fetched from an application cache p471 , and was to be fetched using HTTP GET or
equivalent p56 , and its URL matches the fallback namespace p472 of one or more relevant application
caches p472 , and the user didn't cancel the navigation attempt during the previous step, and the
navigation attempt failed (e.g. the server returned a 4xx or 5xx status code or equivalent p56 , or there
was a DNS error), then:
Let candidate be the fallback resource p471 specified for the fallback namespace p472 in question. If
multiple application caches match, the user agent must use the fallback of the most appropriate
application cache p472 of those that match.
If candidate is not marked as foreign p471 , then the user agent must discard the failed load and instead
continue along these steps using candidate as the resource. The document's address p71 , if appropriate,
will still be the originally requested URL, not the fallback URL, but the user agent may indicate to the
user that the original page load failed, that the page used was a fallback resource, and what the URL of
the fallback resource actually is.
16.
If the document's out-of-band metadata (e.g. HTTP headers), not counting any type information p57 (such
as the Content-Type HTTP header), requires some sort of processing that will not affect the browsing
context, then perform that processing and abort these steps.
Such processing might be triggered by, amongst other things, the following:
•
•
•
HTTP status codes (e.g. 204 No Content or 205 Reset Content)
HTTP Content-Disposition headers
Network errors
HTTP 401 responses that do not include a challenge recognized by the user agent must be processed as
if they had no challenge, e.g. rendering the entity body as if the response had been 200 OK.
User agents may show the entity body of an HTTP 401 response even when the response do include a
recognized challenge, with the option to login being included in a non-modal fashion, to enable the
information provided by the server to be used by the user before authenticating. Similarly, user agents
should allow the user to authenticate (in a non-modal fashion) against authentication challenges
included in other responses such as HTTP 200 OK responses, effectively allowing resources to present
HTTP login forms without requiring their use.
17.
Let type be the sniffed type of the resource p57 .
18.
If the user agent has been configured to process resources of the given type using some mechanism
other than rendering the content in a browsing context p439 , then skip this step. Otherwise, if the type is
one of the following types, jump to the appropriate entry in the following list, and process the resource
as described there:
p678
"
↪ "text/html
p679
"
↪ "text/html-sandboxed
Follow the steps given in the HTML document p463 section, and abort these steps.
↪ Any type ending in "+xml"
↪ "application/xml"
↪ "text/xml"
Follow the steps given in the XML document p463 section. If that section determines that the
content is not to be displayed as a generic XML document, then proceed to the next step in
this overall set of steps. Otherwise, abort these steps.
↪ "text/plain"
Follow the steps given in the plain text file p463 section, and abort these steps.
↪ A supported image type
Follow the steps given in the image p464 section, and abort these steps.
↪ A type that will use an external application to render the content in the browsing
context p439
Follow the steps given in the plugin p464 section, and abort these steps.
Setting the document's address: If there is no override URL, then any Document p31 created by
these steps must have its address p71 set to the URL p51 that was originally to be fetched p55 , ignoring any
other data that was used to obtain the resource (e.g. the entity body in the case of a POST submission is
not part of the document's address p71 , nor is the URL of the fallback resource in the case of the original
load having failed and that URL having been found to match a fallback namespace p472 ). However, if
there is an override URL p461 , then any Document p31 created by these steps must have its address p71 set
to that URL p51 instead.
Note: An override URL p461 is set when dereferencing a javascript: URL p491 .
461
Creating a new Document object: When a Document p31 is created as part of the above steps, a new
Window p443 object must be created and associated with the Document p31 , with one exception: if the
browsing context p439 's only entry in its session history p453 is the about:blank p56 Document p31 that was
added when the browsing context p439 was created, and navigation is occurring with replacement
enabled p466 , and that Document p31 has the same origin p451 as the new Document p31 , then the Window p443
object of that Document p31 must be used instead, and the document p445 attribute of the Window p443 object
must be changed to point to the new Document p31 instead.
19.
Non-document content: If, given type, the new resource is to be handled by displaying some sort of
inline content, e.g. a native rendering of the content, an error message because the specified type is not
supported, or an inline prompt to allow the user to select a registered handler p503 for the given type,
then display the inline content p464 and abort these steps.
Note: In the case of a registered handler being used, the algorithm will be reinvoked
with a new URL to handle the request.
20.
Otherwise, the document's type is such that the resource will not affect the browsing context, e.g.
because the resource is to be handed to an external application. Process the resource appropriately.
Some of the sections below, to which the above algorithm defers in certain cases, require the user agent to
update the session history with the new page. When a user agent is required to do this, it must queue a
task p490 to run the following steps:
1.
Unload p469 the Document p31 object of the current entry p453 , with the recycle parameter set to false.
2.
If the navigation was initiated for entry update of an entry
1.
Replace the Document p31 of the entry being updated, and any other entries that
referenced the same document as that entry, with the new Document p31 .
2.
Traverse the history p465 to the new entry.
Note: This can only happen if the entry being updated is no the current entry p453 ,
and can never happen with replacement enabled p466 . (It happens when the user
tried to traverse to a session history entry that no longer had a Document p31
object.)
Otherwise
1.
Remove all the entries in the browsing context p439 's session history p453 after the current
entry p453 . If the current entry p453 is the last entry in the session history, then no entries
are removed.
Note: This doesn't necessarily have to affect p458 the user agent's user
interface.
2.
Remove any tasks p489 queued by the history traversal task source p491 .
3.
Append a new entry at the end of the History p454 object representing the new resource
and its Document p31 object and related state.
4.
Traverse the history p465 to the new entry. If the navigation was initiated with replacement
enabled p466 , then the traversal must itself be initiated with replacement enabled p466 .
3.
The navigation algorithm p459 has now matured.
4.
Fragment identifier loop: Spin the event loop p490 for a user-agent-defined amount of time, as desired by
the user agent implementor. (This is intended to allow the user agent to optimize the user experience in
the face of performance concerns.)
5.
If the Document p31 object has no parser, or its parser has stopped parsing p618 , or the user agent has
reason to believe the user is no longer interested in scrolling to the fragment identifier, then abort these
steps.
6.
Scroll to the fragment identifier p465 given in the document's current address p71 . If this fails to find an
indicated part of the document p465 , then return to the fragment identifier loop step.
The task source p490 for this task p489 is the networking task source p491 .
462
6.5.2 Page load processing model for HTML files
When an HTML document is to be loaded in a browsing context p439 , the user agent must queue a task p490 to create
a Document object p462 , mark it as being an HTML document p71 , create an HTML parser p554 , and associate it with the
document. Each task p489 that the networking task source p491 places on the task queue p489 while the fetching
algorithm p55 runs must then fill the parser's input stream p555 with the fetched bytes and cause the HTML parser p554
to perform the appropriate processing of the input stream.
Note: The input stream p555 converts bytes into characters for use in the tokenizer p566 . This
process relies, in part, on character encoding information found in the real Content-Type
metadata p57 of the resource; the "sniffed type" is not used for this purpose.
When no more bytes are available, the user agent must queue a task p490 for the parser to process the implied EOF
character, which eventually causes a load event to be fired.
After creating the Document p31 object, but before any script execution, certainly before the parser stops p618 , the
user agent must update the session history with the new page p462 .
Note: Application cache selection p483 happens in the HTML parser p594 .
The task source p490 for the two tasks mentioned in this section must be the networking task source p491 .
6.5.3 Page load processing model for XML files
When faced with displaying an XML file inline, user agents must first create a Document object p462 , following the
requirements of the XML and Namespaces in XML recommendations, RFC 3023, DOM3 Core, and other relevant
specifications. [XML] p705 [XMLNS] p705 [RFC3023] p703 [DOMCORE] p701
The actual HTTP headers and other metadata, not the headers as mutated or implied by the algorithms given in
this specification, are the ones that must be used when determining the character encoding according to the rules
given in the above specifications. Once the character encoding is established, the document's character
encoding p75 must be set to that character encoding.
If the root element, as parsed according to the XML specifications cited above, is found to be an html p106 element
with an attribute manifest p106 whose value is not the empty string, then, as soon as the element is inserted into
the document p27 , the user agent must resolve p51 the value of that attribute relative to that element, and if that is
successful, must run the application cache selection algorithm p483 with the resulting absolute URL p52 with any
p51 component removed as the manifest URL, and passing in the newly-created Document p31 .
Otherwise, if the attribute is absent, its value is the empty string, or resolving its value fails, then as soon as the
root element is inserted into the document p27 , the user agent must run the application cache selection
algorithm p483 with no manifest, and passing in the Document p31 .
Note: Because the processing of the manifest p106 attribute happens only once the root element
is parsed, any URLs referenced by processing instructions before the root element (such as
and PIs) will be fetched from the network and cannot be cached.
User agents may examine the namespace of the root Element p31 node of this Document p31 object to perform
namespace-based dispatch to alternative processing tools, e.g. determining that the content is actually a
syndication feed and passing it to a feed handler. If such processing is to take place, abort the steps in this
section, and jump to the next step p462 (labeled "non-document content") in the navigate p459 steps above.
Otherwise, then, with the newly created Document p31 , the user agents must update the session history with the
new page p462 . User agents may do this before the complete document has been parsed (thus achieving
incremental rendering), and must do this before any scripts are to be executed.
Error messages from the parse process (e.g. XML namespace well-formedness errors) may be reported inline by
mutating the Document p31 .
6.5.4 Page load processing model for text files
When a plain text document is to be loaded in a browsing context p439 , the user agent should queue a task p490 to
create a Document object p462 , mark it as being an HTML document p71 , create an HTML parser p554 , associate it with
the document, act as if the tokenizer had emitted a start tag token with the tag name "pre" followed by a single
U+000A LINE FEED (LF) character, and switch the HTML parser p554 's tokenizer to the PLAINTEXT state p567 . Each
task p489 that the networking task source p491 places on the task queue p489 while the fetching algorithm p55 runs must
then fill the parser's input stream p555 with the fetched bytes and cause the HTML parser p554 to perform the
appropriate processing of the input stream.
463
The rules for how to convert the bytes of the plain text document into actual characters are defined in RFC 2046,
RFC 2646, and subsequent versions thereof. [RFC2046] p702 [RFC2646] p703
The document's character encoding p75 must be set to the character encoding used to decode the document.
Upon creation of the Document p31 object, the user agent must run the application cache selection algorithm p483
with no manifest, and passing in the newly-created Document p31 .
When no more bytes are available, the user agent must queue a task p490 for the parser to process the implied EOF
character, which eventually causes a load event to be fired.
After creating the Document p31 object, but potentially before the page has finished parsing, the user agent must
update the session history with the new page p462 .
User agents may add content to the head p106 element of the Document p31 , e.g. linking to a style sheet or an XBL
binding, providing script, giving the document a title p107 , etc.
The task source p490 for the two tasks mentioned in this section must be the networking task source p491 .
6.5.5 Page load processing model for images
When an image resource is to be loaded in a browsing context p439 , the user agent should create a Document
object p462 , mark it as being an HTML document p71 , append an html p106 element to the Document p31 , append a
head p106 element and a body p131 element to the html p106 element, append an img p186 to the body p131 element, and
set the src p186 attribute of the img p186 element to the address of the image.
Then, the user agent must act as if it had stopped parsing p618 .
Upon creation of the Document p31 object, the user agent must run the application cache selection algorithm p483
with no manifest, and passing in the newly-created Document p31 .
After creating the Document p31 object, but potentially before the page has finished fully loading, the user agent
must update the session history with the new page p462 .
User agents may add content to the head p106 element of the Document p31 , or attributes to the img p186 element, e.g.
to link to a style sheet or an XBL binding, to provide a script, to give the document a title p107 , etc.
6.5.6 Page load processing model for content that uses plugins
When a resource that requires an external resource to be rendered is to be loaded in a browsing context p439 , the
user agent should create a Document object p462 , mark it as being an HTML document p71 , append an html p106
element to the Document p31 , append a head p106 element and a body p131 element to the html p106 element, append
an embed p205 to the body p131 element, and set the src p206 attribute of the embed p205 element to the address of the
resource.
Then, the user agent must act as if it had stopped parsing p618 .
Upon creation of the Document p31 object, the user agent must run the application cache selection algorithm p483
with no manifest, and passing in the newly-created Document p31 .
After creating the Document p31 object, but potentially before the page has finished fully loading, the user agent
must update the session history with the new page p462 .
User agents may add content to the head p106 element of the Document p31 , or attributes to the embed p205 element,
e.g. to link to a style sheet or an XBL binding, or to give the document a title p107 .
Note: If the sandboxed plugins browsing context flag p202 was set on the browsing context p439
when the Document p31 was created, the synthesized embed p205 element will fail to render the
content p206 .
6.5.7 Page load processing model for inline content that doesn't have a DOM
When the user agent is to display a user agent page inline in a browsing context p439 , the user agent should create
a Document object p462 , mark it as being an HTML document p71 , and then either associate that Document p31 with a
custom rendering that is not rendered using the normal Document p31 rendering rules, or mutate that Document p31
until it represents the content the user agent wants to render.
Once the page has been set up, the user agent must act as if it had stopped parsing p618 .
464
Upon creation of the Document p31 object, the user agent must run the application cache selection algorithm p483
with no manifest, passing in the newly-created Document p31 .
After creating the Document p31 object, but potentially before the page has been completely set up, the user agent
must update the session history with the new page p462 .
6.5.8 Navigating to a fragment identifier
When a user agent is supposed to navigate to a fragment identifier, then the user agent must queue a task p490 to
run the following steps:
1.
Remove all the entries in the browsing context p439 's session history p453 after the current entry p453 . If the
current entry p453 is the last entry in the session history, then no entries are removed.
Note: This doesn't necessarily have to affect p458 the user agent's user interface.
2.
Remove any tasks p489 queued by the history traversal task source p491 .
3.
Append a new entry at the end of the History p454 object representing the new resource and its
Document p31 object and related state. Its URL p51 must be set to the address to which the user agent was
navigating p459 . The title must be left unset.
4.
Traverse the history p465 to the new entry. This will scroll to the fragment identifier p465 given in what is
now the document's current address p71 .
Note: If the scrolling fails because the relevant ID has not yet been parsed, then the original
navigation p459 algorithm will take care of the scrolling instead, as the last few steps of its
update the session history with the new page p462 algorithm.
When the user agent is required to scroll to the fragment identifier, it must change the scrolling position of the
document, or perform some other action, such that the indicated part of the document p465 is brought to the user's
attention. If there is no indicated part, then the user agent must not scroll anywhere.
The indicated part of the document is the one that the fragment identifier, if any, identifies. The semantics of
the fragment identifier in terms of mapping it to a specific DOM Node is defined by the specification that defines
the MIME type p26 used by the Document p31 (for example, the processing of fragment identifiers for XML MIME
types p27 is the responsibility of RFC3023). [RFC3023] p703
For HTML documents (and HTML MIME types p26 ), the following processing model must be followed to determine
what the indicated part of the document p465 is.
1.
Parse p51 the URL p51 , and let fragid be the p51 component of the URL.
2.
If fragid is the empty string, then the indicated part of the document p465 is the top of the document; stop
the algorithm here.
3.
Let decoded fragid be the result of expanding any sequences of percent-encoded octets in fragid that
are valid UTF-8 sequences into Unicode characters as defined by UTF-8. If any percent-encoded octets in
that string are not valid UTF-8 sequences, then skip this step and the next one.
4.
If this step was not skipped and there is an element in the DOM that has an ID exactly equal to decoded
fragid, then the first such element in tree order is the indicated part of the document p465 ; stop the
algorithm here.
5.
If there is an a p160 element in the DOM that has a name p662 attribute whose value is exactly equal to
fragid (not decoded fragid), then the first such element in tree order is the indicated part of the
document p465 ; stop the algorithm here.
6.
If fragid is an ASCII case-insensitive p33 match for the string top, then the indicated part of the
document p465 is the top of the document; stop the algorithm here.
7.
Otherwise, there is no indicated part of the document p465 .
For the purposes of the interaction of HTML with Selectors' :target pseudo-class, the target element is the
indicated part of the document p465 , if that is an element; otherwise there is no target element p465 . [SELECTORS] p703
6.5.9 History traversal
When a user agent is required to traverse the history to a specified entry, optionally with replacement
enabled p466 , the user agent must act as follows:
465
1.
If there is no longer a Document p31 object for the entry in question, the user agent must navigate p459 the
browsing context to the location for that entry to perform an entry update p462 of that entry, and abort
these steps. The "navigate p459 " algorithm reinvokes this "traverse" algorithm to complete the traversal,
at which point there is a Document p31 object and so this step gets skipped. The navigation must be done
using the same source browsing context p459 as was used the first time this entry was created. (This can
never happen with replacement enabled p466 .)
2.
If the current entry p453 's title was not set by the pushState() p455 or replaceState() p455 methods, then
set its title to the value returned by the document.title p76 IDL attribute.
3.
If appropriate, update the current entry p453 in the browsing context p439 's Document p31 object's
History p454 object to reflect any state that the user agent wishes to persist. The entry is then said to be
an entry with persisted user state.
For example, some user agents might want to persist the scroll position, or the values of form
controls.
4.
1.
If the browsing context is a top-level browsing context p439 , but not an auxiliary browsing
context p440 , and the origin p449 of the Document p31 of the specified entry is not the same p451 as
the origin p449 of the Document p31 of the current entry p453 , then the following sub-sub-steps must
be run:
1. The current browsing context name p442 must be stored with all the entries in the
history that are associated with Document p31 objects with the same origin p451 as the
active document p439 and that are contiguous with the current entry p453 .
2. The browsing context's browsing context name p442 must be unset.
2.
The user agent must make the specified entry's Document p31 object the active document p439 of
the browsing context p439 .
3.
If the specified entry has a browsing context name p442 stored with it, then the following subsub-steps must be run:
1. The browsing context's browsing context name p442 must be set to the name stored
with the specified entry.
2. Any browsing context name p442 stored with the entries in the history that are
associated with Document p31 objects with the same origin p451 as the new active
document p439 , and that are contiguous with the specified entry, must be cleared.
4.
If the specified entry's Document p31 has any input p303 elements whose resulting
autocompletion state p324 is off, invoke the reset algorithm p366 of each of those elements.
5.
If the current document readiness p75 of the specified entry's Document p31 is "complete", queue
a task p490 to fire a pageshow p468 event at the Window p443 object of that Document p31 , but with its
target p31 set to the Document p31 object (and the currentTarget set to the Window p443 object),
using the PageTransitionEvent p468 interface, with the persisted p468 attribute set to true. This
event must not bubble, must not be cancelable, and has no default action.
5.
Set the document's current address p71 to the URL of the specified entry.
6.
If the specified entry has a URL that differs from the current entry p453 's only by its fragment identifier,
and the two share the same Document p31 object, then let hash changed be true, and let old URL be the
URL of the current entry p453 and new URL be the URL of the specified entry. Otherwise, let hash changed
be false.
7.
If the traversal was initiated with replacement enabled, remove the entry immediately before the
specified entry in the session history.
8.
If the specified entry is not an entry with persisted user state p466 , but its URL has a fragment identifier,
scroll to the fragment identifier p465 .
9.
If the entry is an entry with persisted user state p466 , the user agent may update aspects of the document
and its rendering, for instance the scroll position or values of form fields, that it had previously recorded.
10.
466
If the specified entry has a different Document p31 object than the current entry p453 then the user agent
must run the following substeps:
If the specified entry is a state object or the first entry for a Document p31 , the user agent must run the
following substeps:
1.
If the entry is a state object p453 entry, let state be a structured clone p67 of that state object.
Otherwise, let state be null.
2.
Run the appropriate steps according to the conditions described:
p75
is set to the string "complete"
↪ If the current document readiness
Queue a task p490 to fire a popstate p467 event at the Window p443 object of the
Document p31 , using the PopStateEvent p467 interface, with the state p467 attribute set
to the value of state. This event must bubble but not be cancelable and has no
default action.
↪ Otherwise
Let the Document p31 's pending state object be state. (If there was already a
pending state object p467 , the previous one is discarded.)
Note: The event will then be fired just after the load event.
11.
If hash changed is true, then queue a task p490 to fire a hashchange p467 event at the browsing
context p439 's Window p443 object, using the HashChangeEvent p467 interface, with the oldURL p468 attribute
set to old URL and the newURL p468 attribute set to new URL. This event must bubble but not be
cancelable and has no default action.
12.
The current entry p453 is now the specified entry.
The pending state object p467 must be initially null.
The task source p490 for the tasks mentioned above is the DOM manipulation task source p491 .
6.5.9.1 Event definitions
The popstate event is fired when navigating to a session history entry p453 that represents a state object.
interface PopStateEvent : Event {
readonly attribute any state;
void initPopStateEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in any stateArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . state p467
Returns a copy of the information that was provided to pushState() p455 or replaceState() p455 .
The initPopStateEvent() method must initialize the event in a manner analogous to the similarly-named
method in the DOM Events interfaces. [DOMEVENTS] p701
The state attribute represents the context information for the event, or null, if the state represented is the initial
state of the Document p31 .
The hashchange event is fired when navigating to a session history entry p453 whose URL p51 differs from that of the
previous one only in the fragment identifier.
interface HashChangeEvent : Event {
readonly attribute any oldURL;
readonly attribute any newURL;
void initHashChangeEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in DOMString oldURLArg, in DOMString newURLArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . oldURL
p468
Returns the URL p51 of the session history entry p453 that was previously current.
event . newURL p468
Returns the URL p51 of the session history entry p453 that is now current.
The initHashChangeEvent() method must initialize the event in a manner analogous to the similarly-named
method in the DOM Events interfaces. [DOMEVENTS] p701
467
The oldURL attribute represents context information for the event, specifically the URL of the session history
entry p453 that was traversed from.
The newURL attribute represents context information for the event, specifically the URL of the session history
entry p453 that was traversed to.
The pageshow event is fired when traversing to a session history entry p453 .
The pagehide event is fired when traversing from a session history entry p453 .
interface PageTransitionEvent : Event {
readonly attribute any persisted;
void initPageTransitionEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in any persistedArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . persisted p468
Returns false if the page is newly being loaded (and the load event will fire). Otherwise, returns true.
The initPageTransitionEvent() method must initialize the event in a manner analogous to the similarly-named
method in the DOM Events interfaces. [DOMEVENTS] p701
The persisted attribute represents the context information for the event.
6.5.10 Unloading documents
A Document p31 has a salvageable state, which is initially true.
When a user agent is to prompt to unload a document, it must run the following steps.
1.
Let event be a new BeforeUnloadEvent p469 event object with the name beforeunload, which does not
bubble but is cancelable.
2.
Dispatch: Dispatch event at the Document p31 's Window p443 object.
3.
Release the storage mutex p490 .
4.
If any event listeners were triggered by the earlier dispatch step, then set the Document p31 's salvageable
state to false.
5.
If the returnValue p469 attribute of the event object is not the empty string, or if the event was canceled,
then the user agent should ask the user to confirm that they wish to unload the document.
The prompt shown by the user agent may include the string of the returnValue p469 attribute, or some
leading subset thereof. (A user agent may want to truncate the string to 1024 characters for display, for
instance.)
The user agent must pause p491 while waiting for the user's response.
If the user did not confirm the page navigation, then the user agent refused to allow the document
to be unloaded.
468
6.
If this algorithm was invoked by another instance of the "prompt to unload a document" algorithm (i.e.
through the steps below that invoke this algorithm for all descendant browsing contexts), then abort
these steps here.
7.
Let descendants be the list of the descendant browsing contexts p440 of the Document p31 .
8.
If descendants is not an empty list, then for each browsing context p439 b in descendants run the
following substeps:
1.
Prompt to unload p468 the active document p439 of the browsing context p439 b. If the user refused
to allow the document to be unloaded p468 , then the user implicitly also refused to allow this
document to be unloaded p468 ; abort these steps.
2.
If salvageable state of the active document p439 of the browsing context p439 b is false, then set
the salvageable state of this document to false also.
When a user agent is to unload a document, it must run the following steps. These steps are passed an
argument, recycle, which is either true or false, indicating whether the Document p31 object is going to be re-used.
(This is set by the document.open() p99 method.)
1.
Fire a pagehide p468 event at the Window p443 object of the Document p31 , but with its target p31 set to the
Document p31 object (and the currentTarget set to the Window p443 object), using the
PageTransitionEvent p468 interface, with the persisted p468 attribute set to true. This event must not
bubble, must not be cancelable, and has no default action.
2.
Unload event: Fire a simple event p496 named unload at the Document p31 's Window p443 object.
3.
Release the storage mutex p490 .
4.
If any event listeners were triggered by the earlier unload event step, then set the Document p31 object's
salvageable state to false.
5.
Run any unloading document cleanup steps p469 for Document p31 that are defined by this specification or
any other relevant specifications.
6.
If this algorithm was invoked by another instance of the "unload a document" algorithm (i.e. through the
steps below that invoke this algorithm for all descendant browsing contexts), then abort these steps
here.
7.
Let descendants be the list of the descendant browsing contexts p440 of the Document p31 .
8.
If descendants is not an empty list, then for each browsing context p439 b in descendants run the
following substeps:
9.
1.
Unload p469 the active document p439 of the browsing context p439 b with the recycle parameter
set to false.
2.
If salvageable state of the active document p439 of the browsing context p439 b is false, then set
the salvageable state of this document to false also.
If salvageable and recycle are both false, then the Document p31 's browsing context p439 must discard the
Document p447 .
This specification defines the following unloading document cleanup steps. Other specifications can define
more.
1.
If there are any outstanding transactions that have callbacks that involve scripts p487 whose global
object p487 is the Document p31 's Window p443 object, roll them back (without invoking any of the callbacks)
and set the Document p31 's salvageable state to false. [WEBSQL] p704
2.
Close the WebSocket connection of any WebSocket objects that were created by the WebSocket()
constructor visible on the Document p31 's Window p443 object. If this affected any WebSocket objects, the set
Document p31 's salvageable state to false. [WEBSOCKET] p704
3.
If the Document p31 's salvageable state is false, empty the Document p31 's Window p443 's list of active
timeouts p497 and its list of active intervals p497 .
6.5.10.1 Event definition
interface BeforeUnloadEvent : Event {
attribute DOMString returnValue;
};
This box is non-normative. Implementation requirements are given below this box.
event . returnValue
p469
[ = value ]
Returns the current return value of the event (the message to show the user).
Can be set, to update the message.
Note: There are no BeforeUnloadEvent p469 -specific initialization methods.
The returnValue attribute represents the message to show the user. When the event is created, the attribute
must be set to the empty string. On getting, it must return the last value it was set to. On setting, the attribute
must be set to the new value.
469
6.5.11 Aborting a document load
If the user cancels any instance of the fetching algorithm p55 in the context of a Document p31 in a browsing
context p439 , then, if that Document p31 is an active document p439 , the user agent must queue a task p490 to fire a
simple event p496 named abort at that Document p31 's Window p443 object.
6.6 Offline Web applications
6.6.1 Introduction
This section is non-normative.
In order to enable users to continue interacting with Web applications and documents even when their network
connection is unavailable — for instance, because they are traveling outside of their ISP's coverage area —
authors can provide a manifest which lists the files that are needed for the Web application to work offline and
which causes the user's browser to keep a copy of the files for use offline.
To illustrate this, consider a simple clock applet consisting of an HTML page "clock.html", a CSS style sheet
"clock.css", and a JavaScript script "clock.js".
Before adding the manifest, these three files might look like this:
Clock
The time is:
/* clock.css */
output { font: 2em sans-serif; }
/* clock.js */
setTimeout(function () {
document.getElementById('clock').value = new Date();
}, 1000);
If the user tries to open the "clock.html" page while offline, though, the user agent (unless it happens to have it
still in the local cache) will fail with an error.
The author can instead provide a manifest of the three files:
CACHE MANIFEST
clock.html
clock.css
clock.js
With a small change to the HTML file, the manifest (served as text/cache-manifest p681 ) is linked to the
application:
Clock
The time is:
Now, if the user goes to the page, the browser will cache the files and make them available even when the user is
offline.
470
Note: Authors are encouraged to include the main page in the manifest also, but in practice
the page that referenced the manifest is automatically cached even if it isn't explicitly
mentioned.
Note: HTTP cache headers and restrictions on caching pages served over TLS (encrypted,
using https:) are overridden by manifests. Thus, pages will not expire from an application
cache before the user agent has updated it, and even applications served over TLS can be
made to work offline.
6.6.1.1 Event summary
This section is non-normative.
When the user visits a page that declares a manifest, the browser will try to update the cache. It does this by
fetching a copy of the manifest and, if the manifest has changed since the user agent last saw it, redownloading
all the resources it mentions and caching them anew.
As this is going on, a number of events get fired on the ApplicationCache p484 object to keep the script updated as
to the state of the cache update, so that the user can be notified appropriately. The events are as follows:
Event
name
Interface
Dispatched when...
Next events
checking
Event p31
The user agent is checking for an update, or attempting to download the
manifest for the first time. This is always the first event in the
sequence.
noupdate p471 ,
downloading p471 ,
obsolete p471 , error p471
noupdate
Event p31
The manifest hadn't changed.
Last event in sequence.
The user agent has found an update and is fetching it, or is downloading
the resources listed by the manifest for the first time.
progress p471 , error p471 ,
cached p471 , updateready p471
downloading Event p31
progress
ProgressEvent The user agent is downloading resources listed by the manifest.
progress p471 , error p471 ,
cached p471 , updateready p471
cached
Event p31
The resources listed in the manifest have been downloaded, and the
application is now cached.
Last event in sequence.
The resources listed in the manifest have been newly redownloaded, and
the script can use swapCache() p486 to switch to the new cache.
Last event in sequence.
updateready Event p31
obsolete
Event p31
The manifest was found to have become a 404 or 410 page, so the
application cache is being deleted.
Last event in sequence.
error
Event p31
The manifest was a 404 or 410 page, so the attempt to cache the
application has been aborted.
Last event in sequence.
The manifest hadn't changed, but the page referencing the manifest failed
to download properly.
A fatal error occurred while fetching the resources listed in the manifest.
The manifest changed while the update was being run.
The user agent will try
fetching the files again
momentarily.
6.6.2 Application caches
An application cache is a set of cached resources consisting of:
•
One or more resources (including their out-of-band metadata, such as HTTP headers, if any), identified
by URLs, each falling into one (or more) of the following categories:
Master entries
Documents that were added to the cache because a browsing context p439 was navigated p459 to that
document and the document indicated that this was its cache, using the manifest p106 attribute.
The manifest
The resource corresponding to the URL that was given in a master entry's html p106 element's
manifest p106 attribute. The manifest is fetched and processed during the application cache
download process p477 . All the master entries p471 have the same origin p451 as the manifest.
Explicit entries
Resources that were listed in the cache's manifest p471 in an explicit section p474 . Explicit entries can
also be marked as foreign, which means that they have a manifest p106 attribute but that it
doesn't point at this cache's manifest p471 .
Fallback entries
Resources that were listed in the cache's manifest p471 in a fallback section p474 .
471
Note: A URL in the list can be flagged with multiple different types, and thus an entry
can end up being categorized as multiple entries. For example, an entry can be a
manifest entry and an explicit entry at the same time, if the manifest is listed within
the manifest.
•
Zero or more fallback namespaces: URLs, used as prefix match patterns p472 , each of which is mapped
to a fallback entry p471 . Each namespace URL has the same origin p451 as the manifest p471 .
•
Zero or more URLs that form the online whitelist namespaces.
•
An online whitelist wildcard flag, which is either open or blocking.
Each application cache p471 has a completeness flag, which is either complete or incomplete.
An application cache group is a group of application caches p471 , identified by the absolute URL p52 of a resource
manifest p471 which is used to populate the caches in the group.
An application cache p471 is newer than another if it was created after the other (in other words, application
caches p471 in an application cache group p472 have a chronological order).
Only the newest application cache p471 in an application cache group p472 can have its completeness flag p472 set to
incomplete; the others are always all complete.
Each application cache group p472 has an update status, which is one of the following: idle, checking,
downloading.
A relevant application cache is an application cache p471 that is the newest p472 in its group p472 to be complete.
Each application cache group p472 has a list of pending master entries. Each entry in this list consists of a
resource and a corresponding Document p31 object. It is used during the application cache download process p477 to
ensure that new master entries are cached even if the application cache download process p477 was already
running for their application cache group p472 when they were loaded.
An application cache group p472 can be marked as obsolete, meaning that it must be ignored when looking at what
application cache groups p472 exist.
A cache host is a Document p31 or a SharedWorkerGlobalScope object. A cache host p472 can be associated with an
application cache p471 . [WEBWORKERS] p704
A Document p31 initially is not associated with an application cache p471 , but can become associated with one early
during the page load process, when steps in the parser p594 and in the navigation p459 sections cause cache
selection p483 to occur.
A SharedWorkerGlobalScope can be associated with an application cache p471 when it is created.
[WEBWORKERS] p704
Each cache host p472 has an associated ApplicationCache p484 object.
Multiple application caches p471 in different application cache groups p472 can contain the same resource, e.g. if the
manifests all reference that resource. If the user agent is to select an application cache from a list of relevant
application caches p472 that contain a resource, the user agent must use the application cache that the user most
likely wants to see the resource from, taking into account the following:
•
which application cache was most recently updated,
•
which application cache was being used to display the resource from which the user decided to look at
the new resource, and
•
which application cache the user prefers.
A URL matches a fallback namespace if there exists a relevant application cache p472 whose manifest p471 's URL
has the same origin p451 as the URL in question, and that has a fallback namespace p472 that is a prefix match p33 for
the URL being examined. If multiple fallback namespaces match the same URL, the longest one is the one that
matches. A URL looking for a fallback namespace can match more than one application cache at a time, but only
matches one namespace in each cache.
If a manifest http://example.com/app1/manifest declares that http://example.com/resources/images
is a fallback namespace, and the user navigates to HTTP://EXAMPLE.COM:80/resources/images/cat.png,
then the user agent will decide that the application cache identified by http://example.com/app1/
manifest contains a namespace with a match for that URL.
472
6.6.3 The cache manifest syntax
6.6.3.1 A sample manifest
This section is non-normative.
This example manifest requires two images and a style sheet to be cached and whitelists a CGI script.
CACHE MANIFEST
# the above line is required
# this is a comment
# there can be as many of these anywhere in the file
# they are all ignored
# comments can have spaces before them
# but must be alone on the line
# blank lines are ignored too
# these are files that need to be cached they can either be listed
# first, or a "CACHE:" header could be put before them, as is done
# lower down.
images/sound-icon.png
images/background.png
# note that each file has to be put on its own line
# here is a file for the online whitelist -- it isn't cached, and
# references to this file will bypass the cache, always hitting the
# network (or trying to, if the user is offline).
NETWORK:
comm.cgi
# here is another set of files to cache, this time just the CSS file.
CACHE:
style/default.css
It could equally well be written as follows:
CACHE MANIFEST
NETWORK:
comm.cgi
CACHE:
style/default.css
images/sound-icon.png
images/background.png
The following manifest defines a catch-all error page that is displayed for any page on the site while the user is
offline. It also specifies that the online whitelist wildcard flag p472 is open, meaning that accesses to resources on
other sites will not be blocked. (Resources on the same site are already not blocked because of the catch-all
fallback namespace.)
So long as all pages on the site reference this manifest, they will get cached locally as they are fetched, so that
subsequent hits to the same page will load the page immediately from the cache. Until the manifest is changed,
those pages will not be fetched from the server again. When the manifest changes, then all the files will be
redownloaded.
Subresources, such as style sheets, images, etc, would only be cached using the regular HTTP caching semantics,
however.
CACHE MANIFEST
FALLBACK:
/ /offline.html
NETWORK:
*
6.6.3.2 Writing cache manifests
Manifests must be served using the text/cache-manifest p681 MIME type p26 . All resources served using the text/
cache-manifest p681 MIME type p26 must follow the syntax of application cache manifests, as described in this
section.
473
An application cache manifest is a text file, whose text is encoded using UTF-8. Data in application cache
manifests is line-based. Newlines must be represented by U+000A LINE FEED (LF) characters, U+000D CARRIAGE
RETURN (CR) characters, or U+000D CARRIAGE RETURN (CR) U+000A LINE FEED (LF) pairs.
Note: This is a willful violation p17 of two aspects of RFC 2046, which requires all text/* types
to support an open-ended set of character encodings and only allows CRLF line breaks. These
requirements, however, are outdated; UTF-8 is now widely used, such that supporting other
encodings is no longer necessary, and use of CR, LF, and CRLF line breaks is commonly
supported and indeed sometimes CRLF is not supported by text editors. [RFC2046] p702
The first line of an application cache manifest must consist of the string "CACHE", a single U+0020 SPACE
character, the string "MANIFEST", and either a U+0020 SPACE character, a U+0009 CHARACTER TABULATION (tab)
character, a U+000A LINE FEED (LF) character, or a U+000D CARRIAGE RETURN (CR) character. The first line may
optionally be preceded by a U+FEFF BYTE ORDER MARK (BOM) character. If any other text is found on the first
line, it is ignored.
Subsequent lines, if any, must all be one of the following:
A blank line
Blank lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab)
characters only.
A comment
Comment lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab)
characters, followed by a single U+0023 NUMBER SIGN character (#), followed by zero or more characters
other than U+000A LINE FEED (LF) and U+000D CARRIAGE RETURN (CR) characters.
Note: Comments must be on a line on their own. If they were to be included on a line with
a URL, the "#" would be mistaken for part of a fragment identifier.
A section header
Section headers change the current section. There are three possible section headers:
CACHE:
Switches to the explicit section.
FALLBACK:
Switches to the fallback section.
NETWORK:
Switches to the online whitelist section.
Section header lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION
(tab) characters, followed by one of the names above (including the U+003A COLON character (:)) followed
by zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters.
Ironically, by default, the current section is the explicit section p474 .
Data for the current section
The format that data lines must take depends on the current section.
When the current section is the explicit section p474 , data lines must consist of zero or more U+0020 SPACE
and U+0009 CHARACTER TABULATION (tab) characters, a valid URL p51 identifying a resource other than the
manifest itself, and then zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab)
characters.
When the current section is the fallback section p474 , data lines must consist of zero or more U+0020 SPACE
and U+0009 CHARACTER TABULATION (tab) characters, a valid URL p51 identifying a resource other than the
manifest itself, one or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, another
valid URL p51 identifying a resource other than the manifest itself, and then zero or more U+0020 SPACE and
U+0009 CHARACTER TABULATION (tab) characters.
When the current section is the online whitelist section p474 , data lines must consist of zero or more U+0020
SPACE and U+0009 CHARACTER TABULATION (tab) characters, either a single U+002A ASTERISK character
(*) or a valid URL p51 identifying a resource other than the manifest itself, and then zero or more U+0020
SPACE and U+0009 CHARACTER TABULATION (tab) characters.
Manifests may contain sections more than once. Sections may be empty.
If the manifest's p51 is https: or another scheme intended for encrypted data transfer, then all URLs in
explicit sections p474 must have the same origin p451 as the manifest itself.
474
URLs that are to be fallback pages associated with fallback namespaces p472 , and those namespaces themselves,
must be given in fallback sections p474 , with the namespace being the first URL of the data line, and the
corresponding fallback page being the second URL. All the other pages to be cached must be listed in explicit
sections p474 .
Fallback namespaces p472 and fallback entries p471 must have the same origin p451 as the manifest itself.
A fallback namespace p472 must not be listed more than once.
Namespaces that the user agent is to put into the online whitelist p472 must all be specified in online whitelist
sections p474 . (This is needed for any URL that the page is intending to use to communicate back to the server.) To
specify that all URLs are automatically whitelisted in this way, a U+002A ASTERISK character character (*) may be
specified as one of the URLs.
Authors should not include namespaces in the online whitelist p472 for which another namespace in the online
whitelist p472 is a prefix match p33 .
Relative URLs must be given relative to the manifest's own URL. All URLs in the manifest must have the same
p51 as the manifest itself (either explicitly or implicitly, through the use of relative URLs).
URLs in manifests must not have fragment identifiers (i.e. the U+0023 NUMBER SIGN character isn't allowed in
URLs in manifests).
Fallback namespaces p472 and namespaces in the online whitelist p472 are matched by prefix match p33 .
6.6.3.3 Parsing cache manifests
When a user agent is to parse a manifest, it means that the user agent must run the following steps:
1.
The user agent must decode the byte stream corresponding with the manifest to be parsed, treating it
as UTF-8. Bytes or sequences of bytes that are not valid UTF-8 sequences must be interpreted as a
U+FFFD REPLACEMENT CHARACTER.
2.
Let base URL be the absolute URL p52 representing the manifest.
3.
Let explicit URLs be an initially empty list of absolute URLs p52 for explicit entries p471 .
4.
Let fallback URLs be an initially empty mapping of fallback namespaces p472 to absolute URLs p52 for
fallback entries p471 .
5.
Let online whitelist namespaces be an initially empty list of absolute URLs p52 for an online whitelist p472 .
6.
Let online whitelist wildcard flag be blocking.
7.
Let input be the decoded text of the manifest's byte stream.
8.
Let position be a pointer into input, initially pointing at the first character.
9.
If position is pointing at a U+FEFF BYTE ORDER MARK (BOM) character, then advance position to the
next character.
10.
If the characters starting from position are "CACHE", followed by a U+0020 SPACE character, followed by
"MANIFEST", then advance position to the next character after those. Otherwise, this isn't a cache
manifest; abort this algorithm with a failure while checking for the magic signature.
11.
If the character at position is neither a U+0020 SPACE character, a U+0009 CHARACTER TABULATION
(tab) character, U+000A LINE FEED (LF) character, nor a U+000D CARRIAGE RETURN (CR) character,
then this isn't a cache manifest; abort this algorithm with a failure while checking for the magic
signature.
12.
This is a cache manifest. The algorithm cannot fail beyond this point (though bogus lines can get
ignored).
13.
Collect a sequence of characters p34 that are not U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN
(CR) characters, and ignore those characters. (Extra text on the first line, after the signature, is ignored.)
14.
Let mode be "explicit".
15.
Start of line: If position is past the end of input, then jump to the last step. Otherwise, collect a sequence
of characters p34 that are U+000A LINE FEED (LF), U+000D CARRIAGE RETURN (CR), U+0020 SPACE, or
U+0009 CHARACTER TABULATION (tab) characters.
16.
Now, collect a sequence of characters p34 that are not U+000A LINE FEED (LF) or U+000D CARRIAGE
RETURN (CR) characters, and let the result be line.
475
17.
Drop any trailing U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters at the end of
line.
18.
If line is the empty string, then jump back to the step labeled "start of line".
19.
If the first character in line is a U+0023 NUMBER SIGN character (#), then jump back to the step labeled
"start of line".
20.
If line equals "CACHE:" (the word "CACHE" followed by a U+003A COLON character (:)), then set mode to
"explicit" and jump back to the step labeled "start of line".
21.
If line equals "FALLBACK:" (the word "FALLBACK" followed by a U+003A COLON character (:)), then set
mode to "fallback" and jump back to the step labeled "start of line".
22.
If line equals "NETWORK:" (the word "NETWORK" followed by a U+003A COLON character (:)), then set
mode to "online whitelist" and jump back to the step labeled "start of line".
23.
If line ends with a U+003A COLON character (:), then set mode to "unknown" and jump back to the step
labeled "start of line".
24.
This is either a data line or it is syntactically incorrect.
25.
Let position be a pointer into line, initially pointing at the start of the string.
26.
Let tokens be a list of strings, initially empty.
27.
While position doesn't point past the end of line:
28.
1.
Let current token be an empty string.
2.
While position doesn't point past the end of line and the character at position is neither a
U+0020 SPACE nor a U+0009 CHARACTER TABULATION (tab) character, add the character at
position to current token and advance position to the next character in input.
3.
Add current token to the tokens list.
4.
While position doesn't point past the end of line and the character at position is either a
U+0020 SPACE or a U+0009 CHARACTER TABULATION (tab) character, advance position to the
next character in input.
Process tokens as follows:
↪ If mode is "explicit"
Resolve p51 the first item in tokens, relative to base URL; ignore the rest.
If this fails, then jump back to the step labeled "start of line".
If the resulting absolute URL p52 has a different p51 component than the manifest's
URL (compared in an ASCII case-insensitive p33 manner), then jump back to the step labeled
"start of line". If the manifest's p51 is https: or another scheme intended for
encrypted data transfer, and the resulting absolute URL p52 does not have the same origin p451
as the manifest's URL, then jump back to the step labeled "start of line".
Drop the p51 component of the resulting absolute URL p52 , if it has one.
Add the resulting absolute URL p52 to the explicit URLs.
↪ If mode is "fallback"
Let part one be the first token in tokens, and let part two be the second token in tokens.
Resolve p51 part one and part two, relative to base URL.
If either fails, then jump back to the step labeled "start of line".
If the absolute URL p52 corresponding to either part one or part two does not have the same
origin p451 as the manifest's URL, then jump back to the step labeled "start of line".
Drop any the p51 components of the resulting absolute URLs p52 .
If the absolute URL p52 corresponding to part one is already in the fallback URLs mapping as a
fallback namespace p472 , then jump back to the step labeled "start of line".
Otherwise, add the absolute URL p52 corresponding to part one to the fallback URLs mapping as
a fallback namespace p472 , mapped to the absolute URL p52 corresponding to part two as the
fallback entry p471 .
476
↪ If mode is "online whitelist"
If the first item in tokens is a U+002A ASTERISK character (*), then set online whitelist wildcard
flag to open and jump back to the step labeled "start of line".
Otherwise, resolve p51 the first item in tokens, relative to base URL; ignore the rest.
If this fails, then jump back to the step labeled "start of line".
If the resulting absolute URL p52 has a different p51 component than the manifest's
URL (compared in an ASCII case-insensitive p33 manner), then jump back to the step labeled
"start of line".
Drop the p51 component of the resulting absolute URL p52 , if it has one.
Add the resulting absolute URL p52 to the online whitelist namespaces.
↪ If mode is "unknown"
Do nothing. The line is ignored.
29.
Jump back to the step labeled "start of line". (That step jumps to the next, and last, step when the end of
the file is reached.)
30.
Return the explicit URLs list, the fallback URLs mapping, the online whitelist namespaces, and the online
whitelist wildcard flag.
If a resource is listed in the explicit section p474 or as a fallback entry p471 in the fallback
section p474 , the resource will always be taken from the cache, regardless of any other
matching entries in the fallback namespaces p472 or online whitelist namespaces p472 .
When a fallback namespace p472 and an online whitelist namespace p472 overlap, the online
whitelist namespace p472 has priority.
The online whitelist wildcard flag p472 is applied last, only for URLs that match neither the
online whitelist namespace p472 nor the fallback namespace p472 and that are not listed in the
explicit section p474 .
6.6.4 Downloading or updating an application cache
When the user agent is required (by other parts of this specification) to start the application cache download
process for an absolute URL p52 purported to identify a manifest p471 , or for an application cache group p472 ,
potentially given a particular cache host p472 , and potentially given a master p471 resource, the user agent must run
the steps below. These steps are always run asynchronously, in parallel with the event loop p489 tasks p489 .
Some of these steps have requirements that only apply if the user agent shows caching progress. Support for
this is optional. Caching progress UI could consist of a progress bar or message panel in the user agent's interface,
or an overlay, or something else. Certain events fired during the application cache download process p477 allow the
script to override the display of such an interface. The goal of this is to allow Web applications to provide more
seamless update mechanisms, hiding from the user the mechanics of the application cache mechanism. User
agents may display user interfaces independent of this, but are encouraged to not show prominent update
progress notifications for applications that cancel the relevant events.
Note: These events are delayed until after the load event has fired.
The application cache download process p477 steps are as follows:
1.
Optionally, wait until the permission to start the application cache download process p477 has been
obtained from the user and until the user agent is confident that the network is available. This could
include doing nothing until the user explicitly opts-in to caching the site, or could involve prompting the
user for permission. The algorithm might never get past this point. (This step is particularly intended to
be used by user agents running on severely space-constrained devices or in highly privacy-sensitive
environments).
2.
Atomically, so as to avoid race conditions, perform the following substeps:
1.
Pick the appropriate substeps:
p52
purported to identify a
↪ If these steps were invoked with an absolute URL
manifest p471
Let manifest URL be that absolute URL p52 .
477
If there is no application cache group p472 identified by manifest URL, then create a
new application cache group p472 identified by manifest URL. Initially, it has no
application caches p471 . One will be created later in this algorithm.
p472
↪ If these steps were invoked with an application cache group
Let manifest URL be the absolute URL p52 of the manifest p471 used to identify the
application cache group p472 to be updated.
2.
Let cache group be the application cache group p472 identified by manifest URL.
3.
If these steps were invoked with a master p471 resource, then add the resource, along with the
resource's Document p31 , to cache group's list of pending master entries p472 .
4.
If these steps were invoked with a cache host p472 , and the status p472 of cache group is
checking or downloading, then queue a post-load task p483 to fire a simple event p496 named
checking p471 that is cancelable at the ApplicationCache p484 singleton of that cache host p472 .
The default action of this event must be, if the user agent shows caching progress p477 , the
display of some sort of user interface indicating to the user that the user agent is checking to
see if it can download the application.
5.
If these steps were invoked with a cache host p472 , and the status p472 of cache group is
downloading, then also queue a post-load task p483 to fire a simple event p496 named
downloading p471 that is cancelable at the ApplicationCache p484 singleton of that cache
host p472 . The default action of this event must be, if the user agent shows caching progress p477 ,
the display of some sort of user interface indicating to the user the application is being
downloaded.
6.
If the status p472 of the cache group is either checking or downloading, then abort this instance
of the application cache download process p477 , as an update is already in progress.
7.
Set the status p472 of cache group to checking.
8.
For each cache host p472 associated with an application cache p471 in cache group, queue a postload task p483 to fire a simple event p496 that is cancelable named checking p471 at the
ApplicationCache p484 singleton of the cache host p472 . The default action of these events must
be, if the user agent shows caching progress p477 , the display of some sort of user interface
indicating to the user that the user agent is checking for the availability of updates.
Note: The remainder of the steps run asynchronously.
If cache group already has an application cache p471 in it, then this is an upgrade attempt. Otherwise,
this is a cache attempt.
3.
If this is a cache attempt p478 , then this algorithm was invoked with a cache host p472 ; queue a post-load
task p483 to fire a simple event p496 named checking p471 that is cancelable at the ApplicationCache p484
singleton of that cache host p472 . The default action of this event must be, if the user agent shows
caching progress p477 , the display of some sort of user interface indicating to the user that the user agent
is checking for the availability of updates.
4.
Fetching the manifest: Fetch p55 the resource from manifest URL, and let manifest be that resource.
If the resource is labeled with the MIME type p26 text/cache-manifest p681 , parse manifest according to
the rules for parsing manifests p475 , obtaining a list of explicit entries p471 , fallback entries p471 and the
fallback namespaces p472 that map to them, entries for the online whitelist p472 , and a value for the online
whitelist wildcard flag p472 .
5.
478
If fetching the manifest fails due to a 404 or 410 response or equivalent p56 , then run these substeps:
1.
Mark cache group as obsolete p472 . This cache group no longer exists for any purpose other
than the processing of Document p31 objects already associated with an application cache p471 in
the cache group.
2.
Let task list be an empty list of tasks p489 .
3.
For each cache host p472 associated with an application cache p471 in cache group, create a
task p489 to fire a simple event p496 named obsolete p471 that is cancelable at the
ApplicationCache p484 singleton of the cache host p472 , and add it to task list. The default
action of these events must be, if the user agent shows caching progress p477 , the display of
some sort of user interface indicating to the user that the application is no longer available for
offline use.
4.
For each entry in cache group's list of pending master entries p472 , create a task p489 to fire a
simple event p496 that is cancelable named error p471 (not obsolete p471 !) at the
ApplicationCache p484 singleton of the cache host p472 the Document p31 for this entry, if there
still is one, and add it to task list. The default action of this event must be, if the user agent
shows caching progress p477 , the display of some sort of user interface indicating to the user
that the user agent failed to save the application for offline use.
5.
If cache group has an application cache p471 whose completeness flag p472 is incomplete, then
discard that application cache p471 .
6.
If appropriate, remove any user interface indicating that an update for this cache is in
progress.
7.
Let the status p472 of cache group be idle.
8.
For each task p489 in task list, queue that task as a post-load task p483 .
9.
Abort the application cache download process p477 .
6.
Otherwise, if fetching the manifest fails in some other way (e.g. the server returns another 4xx or 5xx
response or equivalent p56 , or there is a DNS error, or the connection times out, or the user cancels the
download, or the parser for manifests fails when checking the magic signature), or if the server returned
a redirect, or if the resource is labeled with a MIME type p26 other than text/cache-manifest p681 , then
run the cache failure steps p482 .
7.
If this is an upgrade attempt p478 and the newly downloaded manifest is byte-for-byte identical to the
manifest found in the newest p472 application cache p471 in cache group, or the server reported it as "304
Not Modified" or equivalent p56 , then run these substeps:
1.
Let cache be the newest p472 application cache p471 in cache group.
2.
Let task list be an empty list of tasks p489 .
3.
For each entry in cache group's list of pending master entries p472 , wait for the resource for this
entry to have either completely downloaded or failed.
If the download failed (e.g. the connection times out, or the user cancels the download), then
create a task p489 to fire a simple event p496 that is cancelable named error p471 at the
ApplicationCache p484 singleton of the cache host p472 the Document p31 for this entry, if there
still is one, and add it to task list. The default action of this event must be, if the user agent
shows caching progress p477 , the display of some sort of user interface indicating to the user
that the user agent failed to save the application for offline use.
Otherwise, associate the Document p31 for this entry with cache; store the resource for this
entry in cache, if it isn't already there, and categorize its entry as a master entry p471 . If the
resource's URL p51 has a p51 component, it must be removed from the entry in
cache (application caches never include fragment identifiers).
Note: HTTP caching rules, such as Cache-Control: no-store, are ignored for
the purposes of the application cache download process p477 .
4.
For each cache host p472 associated with an application cache p471 in cache group, create a
task p489 to fire a simple event p496 that is cancelable named noupdate p471 at the
ApplicationCache p484 singleton of the cache host p472 , and add it to task list. The default
action of these events must be, if the user agent shows caching progress p477 , the display of
some sort of user interface indicating to the user that the application is up to date.
5.
Empty cache group's list of pending master entries p472 .
6.
If appropriate, remove any user interface indicating that an update for this cache is in
progress.
7.
Let the status p472 of cache group be idle.
8.
For each task p489 in task list, queue that task as a post-load task p483 .
9.
Abort the application cache download process p477 .
8.
Let new cache be a newly created application cache p471 in cache group. Set its completeness flag p472 to
incomplete.
9.
For each entry in cache group's list of pending master entries p472 , associate the Document p31 for this
entry with new cache.
479
10.
Set the status p472 of cache group to downloading.
11.
For each cache host p472 associated with an application cache p471 in cache group, queue a post-load
task p483 to fire a simple event p496 that is cancelable named downloading p471 at the
ApplicationCache p484 singleton of the cache host p472 . The default action of these events must be, if the
user agent shows caching progress p477 , the display of some sort of user interface indicating to the user
that a new version is being downloaded.
12.
Let file list be an empty list of URLs with flags.
13.
Add all the URLs in the list of explicit entries p471 obtained by parsing manifest to file list, each flagged
with "explicit entry".
14.
Add all the URLs in the list of fallback entries p471 obtained by parsing manifest to file list, each flagged
with "fallback entry".
15.
If this is an upgrade attempt p478 , then add all the URLs of master entries p471 in the newest p472 application
cache p471 in cache group whose completeness flag p472 is complete to file list, each flagged with "master
entry".
16.
If any URL is in file list more than once, then merge the entries into one entry for that URL, that entry
having all the flags that the original entries had.
17.
For each URL in file list, run the following steps. These steps may be run in parallel for two or more of
the URLs at a time.
1.
If the resource URL being processed was flagged as neither an "explicit entry" nor or a
"fallback entry", then the user agent may skip this URL.
Note: This is intended to allow user agents to expire resources not listed in
the manifest from the cache. Generally, implementors are urged to use an
approach that expires lesser-used resources first.
2.
For each cache host p472 associated with an application cache p471 in cache group, queue a postload task p483 to fire an event with the name progress p471 , which does not bubble, which is
cancelable, and which uses the ProgressEvent interface, at the ApplicationCache p484
singleton of the cache host p472 . The lengthComputable attribute must be set to true, the
total attribute must be set to the number of files in file list, and the loaded attribute must be
set to the number of number of files in file list that have been either downloaded or skipped so
far. The default action of these events must be, if the user agent shows caching progress p477 ,
the display of some sort of user interface indicating to the user that a file is being downloaded
in preparation for updating the application. [PROGRESS] p702
3.
Fetch p55 the resource, from the origin p449 of the URL p51 manifest URL. If this is an upgrade
attempt p478 , then use the newest p472 application cache p471 in cache group as an HTTP cache,
and honor HTTP caching semantics (such as expiration, ETags, and so forth) with respect to
that cache. User agents may also have other caches in place that are also honored.
Note: If the resource in question is already being downloaded for other
reasons then the existing download process can sometimes be used for the
purposes of this step, as defined by the fetching p55 algorithm.
An example of a resource that might already be being downloaded is a large image on a
Web page that is being seen for the first time. The image would get downloaded to
satisfy the img p186 element on the page, as well as being listed in the cache manifest.
According to the rules for fetching p55 that image only need be downloaded once, and it
can be used both for the cache and for the rendered Web page.
4.
If the previous step fails (e.g. the server returns a 4xx or 5xx response or equivalent p56 , or
there is a DNS error, or the connection times out, or the user cancels the download), or if the
server returned a redirect, then run the first appropriate step from the following list:
↪ If the URL being processed was flagged as an "explicit entry" or a "fallback
entry"
Run the cache failure steps p482 .
Note: Redirects are fatal because they are either indicative of a
network problem (e.g. a captive portal); or would allow resources to
be added to the cache under URLs that differ from any URL that the
networking model will allow access to, leaving orphan entries; or
480
would allow resources to be stored under URLs different than their
true URLs. All of these situations are bad.
p56
↪ If the error was a 404 or 410 HTTP response or equivalent
Skip this resource. It is dropped from the cache.
↪ Otherwise
Copy the resource and its metadata from the newest p472 application cache p471 in
cache group whose completeness flag p472 is complete, and act as if that was the
fetched resource, ignoring the resource obtained from the network.
User agents may warn the user of these errors as an aid to development.
Note: These rules make errors for resources listed in the manifest fatal,
while making it possible for other resources to be removed from caches
when they are removed from the server, without errors, and making nonmanifest resources survive server-side errors.
5.
Otherwise, the fetching succeeded. Store the resource in the new cache.
6.
If the URL being processed was flagged as an "explicit entry" in file list, then categorize the
entry as an explicit entry p471 .
7.
If the URL being processed was flagged as a "fallback entry" in file list, then categorize the
entry as a fallback entry p471 .
8.
If the URL being processed was flagged as an "master entry" in file list, then categorize the
entry as a master entry p471 .
9.
As an optimization, if the resource is an HTML or XML file whose root element is an html p106
element with a manifest p106 attribute whose value doesn't match the manifest URL of the
application cache being processed, then the user agent should mark the entry as being
foreign p471 .
18.
For each cache host p472 associated with an application cache p471 in cache group, queue a post-load
task p483 to fire an event with the name progress p471 , which does not bubble, which is cancelable, and
which uses the ProgressEvent interface, at the ApplicationCache p484 singleton of the cache host p472 .
The lengthComputable attribute must be set to true, the total and the loaded attributes must be set
to the number of number of files in file list. The default action of these events must be, if the user agent
shows caching progress p477 , the display of some sort of user interface indicating to the user that all the
files have been downloaded. [PROGRESS] p702
19.
Store the list of fallback namespaces p472 , and the URLs of the fallback entries p471 that they map to, in
new cache.
20.
Store the URLs that form the new online whitelist p472 in new cache.
21.
Store the value of the new online whitelist wildcard flag p472 in new cache.
22.
For each entry in cache group's list of pending master entries p472 , wait for the resource for this entry to
have either completely downloaded or failed.
If the download failed (e.g. the connection times out, or the user cancels the download), then run these
substeps:
1.
Unassociate the Document p31 for this entry from new cache.
2.
Queue a post-load task p483 to fire a simple event p496 that is cancelable named error p471 at the
ApplicationCache p484 singleton of the Document p31 for this entry, if there still is one. The
default action of this event must be, if the user agent shows caching progress p477 , the display
of some sort of user interface indicating to the user that the user agent failed to save the
application for offline use.
3.
If this is a cache attempt p478 and this entry is the last entry in cache group's list of pending
master entries p472 , then run these further substeps:
1.
Discard cache group and its only application cache p471 , new cache.
2.
If appropriate, remove any user interface indicating that an update for this cache is
in progress.
3.
Abort the application cache download process p477 .
481
4.
Otherwise, remove this entry from cache group's list of pending master entries p472 .
Otherwise, store the resource for this entry in new cache, if it isn't already there, and categorize its entry
as a master entry p471 .
23.
Fetch p55 the resource from manifest URL again, and let second manifest be that resource.
24.
If the previous step failed for any reason, or if the fetching attempt involved a redirect, or if second
manifest and manifest are not byte-for-byte identical, then schedule a rerun of the entire algorithm with
the same parameters after a short delay, and run the cache failure steps p482 .
25.
Otherwise, store manifest in new cache, if it's not there already, and categorize its entry as the
manifest p471 .
26.
Set the completeness flag p472 of new cache to complete.
27.
Let task list be an empty list of tasks p489 .
28.
If this is a cache attempt p478 , then for each cache host p472 associated with an application cache p471 in
cache group, create a task p489 to fire a simple event p496 that is cancelable named cached p471 at the
ApplicationCache p484 singleton of the cache host p472 , and add it to task list. The default action of these
events must be, if the user agent shows caching progress p477 , the display of some sort of user interface
indicating to the user that the application has been cached and that they can now use it offline.
Otherwise, it is an upgrade attempt p478 . For each cache host p472 associated with an application cache p471
in cache group, create a task p489 to fire a simple event p496 that is cancelable named updateready p471 at
the ApplicationCache p484 singleton of the cache host p472 , and add it to task list. The default action of
these events must be, if the user agent shows caching progress p477 , the display of some sort of user
interface indicating to the user that a new version is available and that they can activate it by reloading
the page.
29.
If appropriate, remove any user interface indicating that an update for this cache is in progress.
30.
Set the update status p472 of cache group to idle.
31.
For each task p489 in task list, queue that task as a post-oad task p483 .
The cache failure steps are as follows:
1.
Let task list be an empty list of tasks p489 .
2.
For each entry in cache group's list of pending master entries p472 , run the following further substeps.
These steps may be run in parallel for two or more entries at a time.
Wait for the resource for this entry to have either completely downloaded or failed.
2.
Unassociate the Document p31 for this entry from its application cache p471 , if it has one.
3.
Create a task p489 to fire a simple event p496 that is cancelable named error p471 at the
ApplicationCache p484 singleton of the Document p31 for this entry, if there still is one, and add
it to task list. The default action of these events must be, if the user agent shows caching
progress p477 , the display of some sort of user interface indicating to the user that the user
agent failed to save the application for offline use.
3.
For each cache host p472 still associated with an application cache p471 in cache group, create a task p489 to
fire a simple event p496 that is cancelable named error p471 at the ApplicationCache p484 singleton of the
cache host p472 , and add it to task list. The default action of these events must be, if the user agent
shows caching progress p477 , the display of some sort of user interface indicating to the user that the user
agent failed to save the application for offline use.
4.
Empty cache group's list of pending master entries p472 .
5.
If cache group has an application cache p471 whose completeness flag p472 is incomplete, then discard that
application cache p471 .
6.
If appropriate, remove any user interface indicating that an update for this cache is in progress.
7.
Let the status p472 of cache group be idle.
8.
If this was a cache attempt p478 , discard cache group altogether.
9.
For each task p489 in task list, queue that task as a post-load task p483 .
10.
482
1.
Abort the application cache download process p477 .
Attempts to fetch p55 resources as part of the application cache download process p477 may be done with cachedefeating semantics, to avoid problems with stale or inconsistent intermediary caches.
User agents may invoke the application cache download process p477 , in the background, for any application
cache p471 , at any time (with no cache host p472 ). This allows user agents to keep caches primed and to update
caches even before the user visits a site.
Each Document p31 has a list of pending application cache download process tasks that is used to delay
events fired by the algorithm above until the document's load event has fired. When the Document p31 is created,
the list must be empty.
When the steps above say to queue a post-load task task, where task is a task p489 that dispatches an event on
a target ApplicationCache p484 object target, the user agent must run the appropriate steps from the following list:
If target's Document p31 has completely loaded p619
Queue p490 the task task.
Otherwise
Add task to target's Document p31 's list of pending application cache download process tasks p483 .
The task source p490 for these tasks p489 is the networking task source p491 .
6.6.5 The application cache selection algorithm
When the application cache selection algorithm algorithm is invoked with a Document p31 document and
optionally a manifest URL p51 manifest URL, the user agent must run the first applicable set of steps from the
following list:
p471
, and the URL of
↪ If there is a manifest URL, and document was loaded from an application cache
p471
p472
the manifest
of that cache's application cache group
is not the same as manifest URL
Mark the entry for the resource from which document was taken in the application cache p471 from which
it was loaded as foreign p471 .
Restart the current navigation from the top of the navigation algorithm p459 , undoing any changes that
were made as part of the initial load (changes can be avoided by ensuring that the step to update the
session history with the new page p462 is only ever completed after this application cache selection
algorithm p483 is run, though this is not required).
Note: The navigation will not result in the same resource being loaded, because
"foreign" entries are never picked during navigation.
User agents may notify the user of the inconsistency between the cache manifest and the document's
own metadata, to aid in application development.
p471
↪ If document was loaded from an application cache
Associate document with the application cache p471 from which it was loaded. Invoke, in the background,
the application cache download process p477 for that application cache p471 's application cache group p472 ,
with document as the cache host p472 .
p56
↪ If document was loaded using HTTP GET or equivalent , and, there is a manifest URL, and
p451
manifest URL has the same origin
as document
Invoke, in the background, the application cache download process p477 for manifest URL, with document
as the cache host p472 and with the resource from which document was parsed as the master p471 resource.
↪ Otherwise
The Document p31 is not associated with any application cache p471 .
If there was a manifest URL, the user agent may report to the user that it was ignored, to aid in
application development.
6.6.6 Changes to the networking model
When a cache host p472 is associated with an application cache p471 whose completeness flag p472 is complete, any
and all loads for resources related to that cache host p472 other than those for child browsing contexts p439 must go
through the following steps instead of immediately invoking the mechanisms appropriate to that resource's
scheme:
483
1.
If the resource is not to be fetched using the HTTP GET mechanism or equivalent p56 , or if its URL p51 has a
different p51 component than the application cache p471 's manifest p471 , then fetch p55 the
resource normally and abort these steps.
2.
If the resource's URL is a master entry p471 , the manifest p471 , an explicit entry p471 , or a fallback entry p471 in
the application cache p471 , then get the resource from the cache (instead of fetching it), and abort these
steps.
3.
If there is an entry in the application cache p471 's online whitelist p472 that has the same origin p451 as the
resource's URL and that is a prefix match p33 for the resource's URL, then fetch p55 the resource normally
and abort these steps.
4.
If the resource's URL has the same origin p451 as the manifest's URL, and there is a fallback
namespace p472 f in the application cache p471 that is a prefix match p33 for the resource's URL, then:
Fetch p55 the resource normally. If this results in a redirect to a resource with another origin p449 (indicative
of a captive portal), or a 4xx or 5xx status code or equivalent p56 , or if there were network errors (but not
if the user canceled the download), then instead get, from the cache, the resource of the fallback
entry p471 corresponding to the fallback namespace p472 f. Abort these steps.
5.
If the application cache p471 's online whitelist wildcard flag p472 is open, then fetch p55 the resource
normally and abort these steps.
6.
Fail the resource load as if there had been a generic network error.
Note: The above algorithm ensures that so long as the online whitelist wildcard flag p472 is
blocking, resources that are not present in the manifest p471 will always fail to load (at least,
after the application cache p471 has been primed the first time), making the testing of offline
applications simpler.
6.6.7 Expiring application caches
As a general rule, user agents should not expire application caches, except on request from the user, or after
having been left unused for an extended period of time.
Application caches and cookies have similar implications with respect to privacy (e.g. if the site can identify the
user when providing the cache, it can store data in the cache that can be used for cookie resurrection).
Implementors are therefore encouraged to expose application caches in a manner related to HTTP cookies,
allowing caches to be expunged together with cookies and other origin-specific data.
For example, a user agent could have a "delete site-specific data" feature that clears all cookies, application
caches, local storage, databases, etc, from an origin all at once.
6.6.8 Application cache API
interface ApplicationCache {
// update status
const unsigned short UNCACHED = 0;
const unsigned short IDLE = 1;
const unsigned short CHECKING = 2;
const unsigned short DOWNLOADING = 3;
const unsigned short UPDATEREADY = 4;
const unsigned short OBSOLETE = 5;
readonly attribute unsigned short status;
// updates
void update();
void swapCache();
// events
attribute
attribute
attribute
attribute
attribute
attribute
attribute
attribute
484
Function
Function
Function
Function
Function
Function
Function
Function
onchecking;
onerror;
onnoupdate;
ondownloading;
onprogress;
onupdateready;
oncached;
onobsolete;
};
ApplicationCache implements EventTarget;
This box is non-normative. Implementation requirements are given below this box.
cache = window . applicationCache p485
(In a window.) Returns the ApplicationCache p484 object that applies to the active document p439 of that
Window p443 .
cache = self . applicationCache p485
(In a shared worker.) Returns the ApplicationCache p484 object that applies to the current shared
worker. [WEBWORKERS] p704
cache . status p485
Returns the current status of the application cache, as given by the constants defined below.
cache . update p486 ()
Invokes the application cache download process p477 .
Throws an INVALID_STATE_ERR p70 exception if there is no application cache to update.
cache . swapCache p486 ()
Switches to the most recent application cache, if there is a newer one. If there isn't, throws an
INVALID_STATE_ERR p70 exception.
This does not cause previously-loaded resources to be reloaded; for example, images do not suddenly
get reloaded and style sheets and scripts do not get reparsed or reevaluated. The only change is that
subsequent requests for cached resources will obtain the newer copies.
There is a one-to-one mapping from cache hosts p472 to ApplicationCache p484 objects. The applicationCache
attribute on Window p443 objects must return the ApplicationCache p484 object associated with the Window p443
object's active document p439 . The applicationCache attribute on SharedWorkerGlobalScope objects must return
the ApplicationCache p484 object associated with the worker. [WEBWORKERS] p704
Note: A Window p443 or SharedWorkerGlobalScope object has an associated ApplicationCache p484
object even if that cache host p472 has no actual application cache p471 .
The status attribute, on getting, must return the current state of the application cache p471 that the
ApplicationCache p484 object's cache host p472 is associated with, if any. This must be the appropriate value from
the following list:
UNCACHED (numeric value 0)
The ApplicationCache p484 object's cache host p472 is not associated with an application cache p471 at this
time.
IDLE (numeric value 1)
The ApplicationCache p484 object's cache host p472 is associated with an application cache p471 whose
application cache group p472 's update status p472 is idle, and that application cache p471 is the newest p472 cache
in its application cache group p472 , and the application cache group p472 is not marked as obsolete p472 .
CHECKING (numeric value 2)
The ApplicationCache p484 object's cache host p472 is associated with an application cache p471 whose
application cache group p472 's update status p472 is checking.
DOWNLOADING (numeric value 3)
The ApplicationCache p484 object's cache host p472 is associated with an application cache p471 whose
application cache group p472 's update status p472 is downloading.
UPDATEREADY (numeric value 4)
The ApplicationCache p484 object's cache host p472 is associated with an application cache p471 whose
application cache group p472 's update status p472 is idle, and whose application cache group p472 is not marked
as obsolete p472 , but that application cache p471 is not the newest p472 cache in its group.
OBSOLETE (numeric value 5)
The ApplicationCache p484 object's cache host p472 is associated with an application cache p471 whose
application cache group p472 is marked as obsolete p472 .
485
If the update() method is invoked, the user agent must invoke the application cache download process p477 , in the
background, for the application cache p471 with which the ApplicationCache p484 object's cache host p472 is
associated, but without giving that cache host p472 to the algorithm. If there is no such application cache p471 , or if it
is marked as obsolete p472 , then the method must raise an INVALID_STATE_ERR p70 exception instead.
If the swapCache() method is invoked, the user agent must run the following steps:
1.
Check that ApplicationCache p484 object's cache host p472 is associated with an application cache p471 . If it
is not, then raise an INVALID_STATE_ERR p70 exception and abort these steps.
2.
Let cache be the application cache p471 with which the ApplicationCache p484 object's cache host p472 is
associated. (By definition, this is the same as the one that was found in the previous step.)
3.
If cache's application cache group p472 is marked as obsolete p472 , then unassociate the
ApplicationCache p484 object's cache host p472 from cache and abort these steps. (Resources will now
load from the network instead of the cache.)
4.
Check that there is an application cache in the same application cache group p472 as cache whose
completeness flag p472 is complete and that is newer p472 than cache. If there is not, then raise an
INVALID_STATE_ERR p70 exception and abort these steps.
5.
Let new cache be the newest p472 application cache p471 in the same application cache group p472 as cache
whose completeness flag p472 is complete.
6.
Unassociate the ApplicationCache p484 object's cache host p472 from cache and instead associate it with
new cache.
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported, as IDL attributes, by all objects implementing the ApplicationCache p484 interface:
Event handler p492 Event handler event type p493
onchecking
checking p471
onerror
error p471
onnoupdate
noupdate p471
ondownloading
downloading p471
onprogress
progress p471
onupdateready
updateready p471
oncached
cached p471
onobsolete
obsolete p471
6.6.9 Browser state
This box is non-normative. Implementation requirements are given below this box.
window . navigator
p502
. onLine p486
Returns false if the user agent is definitely offline (disconnected from the network). Returns true if the
user agent might be online.
The navigator.onLine attribute must return false if the user agent will not contact the network when the user
follows links or when a script requests a remote page (or knows that such an attempt would fail), and must return
true otherwise.
When the value that would be returned by the navigator.onLine p486 attribute of the Window p443 changes from true
to false, the user agent must queue a task p490 to fire a simple event p496 named offline at the Window p443 object.
On the other hand, when the value that would be returned by the navigator.onLine p486 attribute of the
Window p443 changes from false to true, the user agent must queue a task p490 to fire a simple event p496 named
online at the Window p443 object.
The task source p490 for these tasks p489 is the networking task source p491 .
Note: This attribute is inherently unreliable. A computer can be connected to a network
without having Internet access.
486
7 Web application APIs
7.1 Scripting
7.1.1 Introduction
Various mechanisms can cause author-provided executable code to run in the context of a document. These
mechanisms include, but are probably not limited to:
•
Processing of script p122 elements.
•
Processing of inline javascript: p491 URLs (e.g. the src p186 attribute of img p186 elements, or an @import
rule in a CSS style p119 element block).
•
Event handlers, whether registered through the DOM using addEventListener(), by explicit event
handler content attributes p492 , by event handler IDL attributes p492 , or otherwise.
•
Processing of technologies like XBL or SVG that have their own scripting features.
7.1.2 Enabling and disabling scripting
Scripting is enabled in a browsing context p439 when all of the following conditions are true:
•
The user agent supports scripting.
•
The user has not disabled scripting for this browsing context p439 at this time. (User agents may provide
users with the option to disable scripting globally, or in a finer-grained manner, e.g. on a per-origin
basis.)
•
The browsing context p439 did not have the sandboxed scripts browsing context flag p203 set when the
browsing context p439 's active document p439 was created.
Scripting is disabled in a browsing context p439 when any of the above conditions are false (i.e. when scripting is
not enabled p487 ).
Scripting is enabled for a node if the Document p31 object of the node (the node itself, if it is itself a Document p31
object) has an associated browsing context p439 , and scripting is enabled p487 in that browsing context p439 .
Scripting is disabled for a node if there is no such browsing context p439 , or if scripting is disabled p487 in that
browsing context p439 .
7.1.3 Processing model
7.1.3.1 Definitions
A script has:
A script execution environment
The characteristics of the script execution environment depend on the language, and are not defined by this
specification.
In JavaScript, the script execution environment consists of the interpreter, the stack of execution
contexts, the global code and function code and the Function objects resulting, and so forth.
A list of code entry-points
Each code entry-point represents a block of executable code that the script exposes to other scripts and to
the user agent.
Each Function object in a JavaScript script execution environment p487 has a corresponding code entrypoint, for instance.
The main program code of the script, if any, is the initial code entry-point. Typically, the code
corresponding to this entry-point is executed immediately after the script is parsed.
In JavaScript, this corresponds to the execution context of the global code.
A relationship with the script's global object
An object that provides the APIs that the code can use.
This is typically a Window p443 object. In JavaScript, this corresponds to the global object.
487
Note: When a script's global object p487 is an empty object, it can't do anything that
interacts with the environment.
If the script's global object p487 is a Window p443 object, then in JavaScript, the ThisBinding of the global
execution context for this script must be the Window p443 object's WindowProxy p449 object, rather than the
global object. [ECMA262] p701
Note: This is a willful violation p17 of the JavaScript specification current at the time of
writing (ECMAScript edition 5, as defined in section 10.4.1.1 Initial Global Execution
Context, step 3). The JavaScript specification requires that the this keyword in the global
scope return the global object, but this is not compatible with the security design
prevalent in implementations as specified herein. [ECMA262] p701
A relationship with the script's browsing context
A browsing context p439 that is assigned responsibility for actions taken by the script.
When a script creates and navigates p459 a new top-level browsing context p439 , the opener p441 attribute
of the new browsing context p439 's Window p443 object will be set to the script's browsing context p488 's
WindowProxy p449 object.
A relationship with the script's document
A Document p31 that is assigned responsibility for actions taken by the script.
When a script fetches p55 a resource, the current address p71 of the script's document p488 will be used to
set the Referer (sic) header.
A URL character encoding
A character encoding, set when the script is created, used to encode URLs. If the character encoding is set
from another source, e.g. a document's character encoding p75 , then the script's URL character encoding p488
must follow the source, so that if the source's changes, so does the script's.
A base URL
A URL p51 , set when the script is created, used to resolve relative URLs. If the base URL is set from another
source, e.g. a document base URL p52 , then the script's base URL p488 must follow the source, so that if the
source's changes, so does the script's.
7.1.3.2 Calling scripts
When a user agent is to jump to a code entry-point for a script p487 , for example to invoke an event listener
defined in that script p487 , the user agent must run the following steps:
1.
If the script's global object p487 is a Window p443 object whose Document p31 object is not fully active p440 , then
abort these steps without doing anything. The callback is not fired.
2.
Set the entry script p441 to be the script p487 being invoked.
3.
Make the script execution environment p487 for the script p487 execute the code for the given code entrypoint.
4.
Set the entry script p441 back to whatever it was when this algorithm started.
This algorithm is not invoked by one script calling another.
7.1.3.3 Creating scripts
When the specification says that a script p487 is to be created, given some script source, its scripting language, a
global object, a browsing context, a URL character encoding, and a base URL, the user agent must run the
following steps:
488
1.
If scripting is disabled p487 for browsing context p439 passed to this algorithm, then abort these steps, as if
the script did nothing but return void.
2.
Set up a script execution environment p487 as appropriate for the scripting language.
3.
Parse/compile/initialize the source of the script using the script execution environment p487 , as
appropriate for the scripting language, and thus obtain the list of code entry-points p487 for the script. If
the semantics of the scripting language and the given source code are such that there is executable
code to be immediately run, then the initial code entry-point p487 is the entry-point for that code.
4.
Set up the script's global object p487 , the script's browsing context p488 , the script's document p488 , the
script's URL character encoding p488 , and the script's base URL p488 from the settings passed to this
algorithm.
5.
Jump p488 to the script p487 's initial code entry-point p487 .
When the user agent is to create an impotent script, given some script source, its scripting language, and a
browsing context, the user agent must create a script p488 , using the given script source and scripting language,
using a new empty object as the global object, and using the given browsing context as the browsing context. The
URL character encoding and base URL for the resulting script p487 are not important as no APIs are exposed to the
script.
When the specification says that a script p487 is to be created from a node node, given some script source and its
scripting language, the user agent must create a script p488 , using the given script source and scripting language,
and using the script settings determined from the node p489 node.
The script settings determined from the node node are computed as follows:
1.
Let document be the Document p31 of node (or node itself if it is a Document p31 ).
2.
The browsing context is the browsing context p439 of document.
3.
The global object is the Window p443 object of document.
4.
The URL character encoding is the character encoding p75 of document. (This is a reference, not a
copy p488 .)
5.
The base URL is the base URL p52 of document. (This is a reference, not a copy p488 .)
7.1.3.4 Killing scripts
User agents may impose resource limitations on scripts, for example CPU quotas, memory limits, total execution
time limits, or bandwidth limitations. When a script exceeds a limit, the user agent may either throw a
QUOTA_EXCEEDED_ERR p70 exception, abort the script without an exception, prompt the user, or throttle script
execution.
For example, the following script never terminates. A user agent could, after waiting for a few seconds,
prompt the user to either terminate the script or let it continue.
User agents are encouraged to allow users to disable scripting whenever the user is prompted either by a script
(e.g. using the window.alert() p499 API) or because of a script's actions (e.g. because it has exceeded a time
limit).
If scripting is disabled while a script is executing, the script should be terminated immediately.
7.1.4 Event loops
7.1.4.1 Definitions
To coordinate events, user interaction, scripts, rendering, networking, and so forth, user agents must use event
loops as described in this section.
There must be at least one event loop p489 per user agent, and at most one event loop p489 per unit of related
similar-origin browsing contexts p441 .
An event loop p489 always has at least one browsing context p439 . If an event loop p489 's browsing contexts p439 all go
away, then the event loop p489 goes away as well. A browsing context p439 always has an event loop p489 coordinating
its activities.
Note: Other specifications can define new kinds of event loops that aren't associated with
browsing contexts; in particular, the Web Workers specification does so.
An event loop p489 has one or more task queues. A task queue p489 is an ordered list of tasks, which can be:
Events
Asynchronously dispatching an Event p31 object at a particular EventTarget p31 object is a task.
489
Note: Not all events are dispatched using the task queue p489 , many are dispatched
synchronously during other tasks.
Parsing
The HTML parser p554 tokenizing a single byte, and then processing any resulting tokens, is a task.
Callbacks
Calling a callback asynchronously is a task.
Using a resource
When an algorithm fetches p55 a resource, if the fetching occurs asynchronously then the processing of the
resource once some or all of the resource is available is a task.
Reacting to DOM manipulation
Some elements have tasks that trigger in response to DOM manipulation, e.g. when that element is inserted
into the document p27 .
When a user agent is to queue a task, it must add the given task to one of the task queues p489 of the relevant
event loop p489 . All the tasks from one particular task source (e.g. the callbacks generated by timers, the events
dispatched for mouse movements, the tasks queued for the parser) must always be added to the same task
queue p489 , but tasks from different task sources p490 may be placed in different task queues p489 .
For example, a user agent could have one task queue p489 for mouse and key events (the user interaction
task source p491 ), and another for everything else. The user agent could then give keyboard and mouse
events preference over other tasks three quarters of the time, keeping the interface responsive but not
starving other task queues, and never processing events from any one task source p490 out of order.
Each task p489 that is queued p490 onto a task queue p489 of an event loop p489 defined by this specification is
associated with a Document p31 ; if the task was queued in the context of an element, then it is the element's
Document p31 ; if the task was queued in the context of a browsing context p439 , then it is the browsing context p439 's
active document p439 at the time the task was queued; if the task was queued by or for a script p487 then the
document is the script's document p488 .
A user agent is required to have one storage mutex. This mutex is used to control access to shared state like
cookies. At any one point, the storage mutex p490 is either free, or owned by a particular event loop p489 or instance
of the fetching p55 algorithm.
Whenever a script p487 calls into a plugin p27 , and whenever a plugin p27 calls into a script p487 , the user agent must
release the storage mutex p490 .
7.1.4.2 Processing model
An event loop p489 must continually run through the following steps for as long as it exists:
1.
Run the oldest task p489 on one of the event loop p489 's task queues p489 , ignoring tasks whose associated
Document p31 s are not fully active p440 . The user agent may pick any task queue p489 .
2.
If the storage mutex p490 is now owned by the event loop p489 , release it so that it is once again free.
3.
Remove that task from its task queue p489 .
4.
If any asynchronously-running algorithms are awaiting a stable state, then run their synchronous
section and then resume running their asynchronous algorithm.
Note: A synchronous section p490 never mutates the DOM, runs any script, or has any
other side-effects.
Note: Steps in synchronous sections p490 are marked with ?.
5.
If necessary, update the rendering or user interface of any Document p31 or browsing context p439 to reflect
the current state.
6.
Return to the first step of the event loop p489 .
When an algorithm says to spin the event loop until a condition goal is met, the user agent must run the
following steps:
1.
490
Let task source be the task source p490 of the currently running task p489 .
2.
Stop the currently running task p489 , allowing the event loop p489 to resume, but continue these steps
asynchronously.
3.
Wait until the condition goal is met.
4.
Queue a task p490 to continue running these steps, using the task source p490 task source. Wait until this
task runs before continuing these steps.
5.
Return to the caller.
Some of the algorithms in this specification, for historical reasons, require the user agent to pause while running a
task p489 until some condition has been met. While a user agent has a paused task p489 , the corresponding event
loop p489 must not run further tasks p489 , and any script in the currently running task p489 must block. User agents
should remain responsive to user input while paused, however, albeit in a reduced capacity since the event
loop p489 will not be doing anything.
When a user agent is to obtain the storage mutex as part of running a task p489 , it must run through the
following steps:
1.
If the storage mutex p490 is already owned by this task p489 's event loop p489 , then abort these steps.
2.
Otherwise, pause p491 until the storage mutex p490 can be taken by the event loop p489 .
3.
Take ownership of the storage mutex p490 .
7.1.4.3 Generic task sources
The following task sources p490 are used by a number of mostly unrelated features in this and other specifications.
The DOM manipulation task source
This task source p490 is used for features that react to DOM manipulations, such as things that happen
asynchronously when an element is inserted into the document p27 .
The user interaction task source
This task source p490 is used for features that react to user interaction, for example keyboard or mouse input.
Asynchronous events sent in response to user input (e.g. click p31 events) must be dispatched using
tasks p489 queued p490 with the user interaction task source p491 . [DOMEVENTS] p701
The networking task source
This task source p490 is used for features that trigger in response to network activity.
The history traversal task source
This task source p490 is used to queue calls to history.back() p454 and similar APIs.
7.1.5 The javascript: protocol
When a URL p51 using the javascript: protocol is dereferenced, the user agent must run the following steps:
1.
Let the script source be the string obtained using the content retrieval operation defined for
javascript: URLs. [JSURL] p701
2.
Use the appropriate step from the following list:
If a browsing context p439 is being navigated p459 to a javascript: URL, and the active
document p439 of that browsing context has the same origin p451 as the script given by that
URL
Let address be the address p71 of the active document p439 of the browsing context p439 being
navigated.
If address is about:blank p56 , and the browsing context p439 being navigated has a creator browsing
context p439 , then let address be the address p71 of the creator Document p439 instead.
Create a script p489 from the Document p31 node of the active document p439 , using the
aforementioned script source, and assuming the scripting language is JavaScript.
Let result be the return value of the initial code entry-point p487 of this script p487 . If an exception was
raised, let result be void instead. (The result will be void also if scripting is disabled p487 .)
491
When it comes time to set the document's address p461 in the navigation algorithm p459 , use address
as the override URL p461 .
If the Document p31 object of the element, attribute, or style sheet from which the javascript:
URL was reached has an associated browsing context p439
Create an impotent script p489 using the aforementioned script source, with the scripting language
set to JavaScript, and with the Document p31 's object's browsing context p439 as the browsing context.
Let result be the return value of the initial code entry-point p487 of this script p487 . If an exception was
raised, let result be void instead. (The result will be void also if scripting is disabled p487 .)
Otherwise
Let result be void.
3.
If the result of executing the script is void (there is no return value), then the URL must be treated in a
manner equivalent to an HTTP resource with an HTTP 204 No Content response.
Otherwise, the URL must be treated in a manner equivalent to an HTTP resource with a 200 OK response
whose Content-Type metadata p57 is text/html p678 and whose response body is the return value
converted to a string value.
Note: Certain contexts, in particular img p186 elements, ignore the Content-Type
metadata p57 .
So for example a javascript: URL for a src p186 attribute of an img p186 element would be evaluated in the
context of an empty object as soon as the attribute is set; it would then be sniffed to determine the image
type and decoded as an image.
A javascript: URL in an href p383 attribute of an a p160 element would only be evaluated when the link was
followed p384 .
The src p200 attribute of an iframe p199 element would be evaluated in the context of the iframe p199 's own
browsing context p439 ; once evaluated, its return value (if it was not void) would replace that browsing
context p439 's document, thus changing the variables visible in that browsing context p439 .
7.1.6 Events
7.1.6.1 Event handlers
Many objects can have event handlers specified. These act as bubbling event listeners for the object on which
they are specified.
An event handler p492 can either have the value null or be set to a Function p494 object. Initially, event handlers
must be set to null.
Event handlers are exposed in one or two ways.
The first way, common to all event handlers, is as an event handler IDL attribute p492 .
The second way is as an event handler content attribute p492 . Event handlers on HTML elements p26 and some of the
event handlers on Window p443 objects are exposed in this way.
Event handler IDL attributes, on setting, must set the corresponding event handler to their new value, and on
getting, must return whatever the current value of the corresponding event handler is (possibly null).
If an event handler IDL attribute p492 exposes an event handler p492 of an object that doesn't exist, it must always
return null on getting and must do nothing on setting.
Note: This can happen in particular for event handler IDL attribute p492 on body p131 elements
that do not have corresponding Window p443 objects.
Note: Certain event handler IDL attributes have additional requirements, in particular the
onmessage p546 attribute of MessagePort p544 objects.
Event handler content attributes, when specified, must contain valid JavaScript code matching the
FunctionBody production. [ECMA262] p701
492
When an event handler content attribute p492 is set, if the element is owned by a Document p31 that is in a browsing
context p439 , and scripting is enabled p487 for that browsing context p439 , the user agent must run the following steps
to create a script p487 after setting the content attribute to its new value:
1.
Set up a script execution environment p487 for JavaScript.
2.
Using this script execution environment, create a function object (as defined in ECMAScript edition 5
section 13.2 Creating Function Objects), with:
Parameter list FormalParameterList
p495
attribute of the Window p443 object
↪ If the attribute is the onerror
Let the function have three arguments, named event, source, and fileno.
↪ Otherwise
Let the function have a single argument called event.
Function body FunctionBody
The event handler content attribute p492 's new value.
Lexical Environment Scope
1.
Let Scope be the result of NewObjectEnvironment(the element's Document p31 , the global
environment).
2.
If the element has a form owner p353 , let Scope be the result of
NewObjectEnvironment(the element's form owner p353 , Scope).
3.
Let Scope be the result of NewObjectEnvironment(the element's object, Scope).
Note: NewObjectEnvironment() is defined in ECMAScript edition 5 section
10.2.2.3 NewObjectEnvironment (O, E). [ECMA262] p701
Boolean flag Strict
False.
Let this new function be the only entry in the script's list of code entry-points p487 .
3.
If the previous steps failed to compile the script, then set the corresponding event handler p492 to null and
abort these steps.
4.
Set up the script's global object p487 , the script's browsing context p488 , the script's document p488 , the
script's URL character encoding p488 , and the script's base URL p488 from the script settings determined
from the node p489 on which the attribute is being set.
5.
Set the corresponding event handler p492 to the aforementioned function.
When an event handler content attribute is removed, the user agent must set the corresponding event handler p492
to null.
Note: When an event handler content attribute p492 is set on an element owned by a Document p31
that is not in a browsing context p439 , the corresponding event handler is not changed.
All event handlers p492 on an object, whether an element or some other object, and whether set to null or to a
Function p494 object, must be registered as event listeners on the object when it is created, as if the
addEventListener() method on the object's EventTarget p31 interface had been invoked, with the event type
(type argument) equal to the type corresponding to the event handler (the event handler event type), the
listener set to be a target and bubbling phase listener (useCapture argument set to false), and the event listener
itself (listener argument) set to do nothing while the event handler's value is not a Function p494 object, and set to
invoke the call() p494 callback of the Function p494 object associated with the event handler otherwise.
Note: Event handlers p492 therefore always fire before event listeners attached using
addEventListener().
Note: The listener argument is emphatically not the event handler p492 itself.
Note: The interfaces implemented by the event object do not influence whether an event
handler p492 is triggered or not.
When an event handler p492 's Function p494 object is invoked, its call() p494 callback must be invoked with one
argument, set to the Event p31 object of the event in question.
493
The handler's return value must then be processed as follows:
↪ If the event type is mouseover
If the return value is a boolean with the value true, then the event must be canceled.
p469
object
↪ If the event object is a BeforeUnloadEvent
If the return value is a string, and the event object's returnValue p469 attribute's value is the empty
string, then set the returnValue p469 attribute's value to the return value.
↪ Otherwise
If the return value is a boolean with the value false, then the event must be canceled.
The Function p494 interface represents a function in the scripting language being used. It is represented in IDL as
follows:
[Callback=FunctionOnly, NoInterfaceObject]
interface Function {
any call(in any... arguments);
};
The call(...) method is the object's callback.
Note: In JavaScript, any Function object implements this interface.
If the Function p494 object is a JavaScript Function, then when it is invoked by the user agent, the user agent must
set the thisArg (as defined by ECMAScript edition 5 section 10.4.3 Entering Function Code) to the event
handler p492 's object. [ECMA262] p701
For example, the following document fragment:
...leads to an alert saying "[object Window]" when the document is loaded, and an alert saying
"[object HTMLBodyElement]" whenever the user clicks something in the page.
The return value of the function is affects whether the event is canceled or not: as described above, if the return
value is false, the event is canceled (except for mouseover events, where the return value has to be true to cancel
the event). With beforeunload events, the value is instead used to determine the message to show the user.
7.1.6.2 Event handlers on elements, Document p31 objects, and Window p443 objects
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported by all HTML elements p26 , as both content attributes and IDL attributes, and on Document p31 and
Window p443 objects, as IDL attributes.
Event handler p492
494
Event handler event type p493
onabort
abort
oncanplay
canplay p237
oncanplaythrough
canplaythrough p237
onchange
change
onclick
click p31
oncontextmenu
contextmenu
ondblclick
dblclick
ondrag
drag p526
ondragend
dragend p526
ondragenter
dragenter p526
ondragleave
dragleave p526
ondragover
dragover p526
ondragstart
dragstart p526
ondrop
drop p526
ondurationchange
durationchange p238
onemptied
emptied p237
onended
ended p238
onformchange
formchange
onforminput
forminput
oninput
input
oninvalid
invalid
Event handler p492
Event handler event type p493
onkeydown
keydown
onkeypress
keypress
onkeyup
keyup
onloadeddata
loadeddata p237
onloadedmetadata
loadedmetadata p237
onloadstart
loadstart p237
onmousedown
mousedown
onmousemove
mousemove
onmouseout
mouseout
onmouseover
mouseover
onmouseup
mouseup
onmousewheel
mousewheel
onpause
pause p237
onplay
play p237
onplaying
playing p237
onprogress
progress p237
onratechange
ratechange p238
onreadystatechange readystatechange
onscroll
scroll
onseeked
seeked p237
onseeking
seeking p237
onselect
select
onshow
show
onstalled
stalled p237
onsubmit
submit
onsuspend
suspend p237
ontimeupdate
timeupdate p237
onvolumechange
volumechange p238
onwaiting
waiting p237
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported by all HTML elements p26 other than body p131 , as both content attributes and IDL attributes, and on
Document p31 objects, as IDL attributes:
Event handler p492 Event handler event type p493
onblur
blur
onerror
error
onfocus
focus
onload
load
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported by Window p443 objects, as IDL attributes on the Window p443 object, and with corresponding content
attributes and IDL attributes exposed on the body p131 and frameset p668 elements:
Event handler p492 Event handler event type p493
onafterprint
afterprint
onbeforeprint
beforeprint
onbeforeunload
beforeunload
onblur
blur
onerror
error
onfocus
focus
onhashchange
hashchange p467
onload
load
onmessage
message p540
onoffline
offline p486
ononline
online p486
onpagehide
pagehide p468
onpageshow
pageshow p468
onpopstate
popstate p467
onredo
redo p534
onresize
resize
495
Event handler p492 Event handler event type p493
onstorage
storage
onundo
undo p534
onunload
unload
Note: The onerror p495 handler is also used for reporting script errors p496 .
7.1.6.3 Event firing
Certain operations and methods are defined as firing events on elements. For example, the click() p508 method on
the HTMLElement p81 interface is defined as firing a click p31 event on the element. [DOMEVENTS] p701
Firing a click event means that a click p31 event, which bubbles and is cancelable, and which uses the
MouseEvent interface, must be dispatched at the given target. The event object must have its screenX, screenY,
clientX, clientY, and button attributes set to 0, its ctrlKey, shiftKey, altKey, and metaKey attributes set
according to the current state of the key input device, if any (false for any keys that are not available), its detail
attribute set to 1, and its relatedTarget attribute set to null. The getModifierState() method on the object
must return values appropriately describing the state of the key input device at the time the event is created.
Firing a simple event named e means that an event with the name e, which does not bubble (except where
otherwise stated) and is not cancelable (except where otherwise stated), and which uses the Event p31 interface,
must be dispatched at the given target.
The default action of these event is to do nothing except where otherwise stated.
7.1.6.4 Events and the Window p443 object
When an event is dispatched at a DOM node in a Document p31 in a browsing context p439 , if the event is not a load
event, the user agent must also dispatch the event to the Window p443 , as follows:
1.
In the capture phase, the event must propagate to the Window p443 object before propagating to any of
the nodes, as if the Window p443 object was the parent of the Document p31 in the dispatch chain.
2.
In the bubble phase, the event must propagate up to the Window p443 object at the end of the phase,
unless bubbling has been prevented, again as if the Window p443 object was the parent of the Document p31
in the dispatch chain.
7.1.6.5 Runtime script errors
This section only applies to user agents that support scripting in general and JavaScript in particular.
Whenever an uncaught runtime script error occurs in one of the scripts associated with a Document p31 , the user
agent must report the error p496 using the onerror p495 event handler p492 of the script's global object p487 . If the error
is still not handled p496 after this, then the error may be reported to the user.
When the user agent is required to report an error error using the event handler p492 onerror, it must run these
steps, after which the error is either handled or not handled:
p494
↪ If the value of onerror is a Function
The function must be invoked with three arguments. The three arguments passed to the function are all
DOMStrings; the first must give the message that the UA is considering reporting, the second must give
the absolute URL p52 of the resource in which the error occurred, and the third must give the line number
in that resource on which the error occurred.
If the function returns false, then the error is handled p496 . Otherwise, the error is not handled p496 .
Any uncaught exceptions thrown or errors caused by this function may be reported to the user
immediately after the error that the function was called for; the report an error p496 algorithm must not be
used to handle exceptions thrown or errors caused by this function.
↪ Otherwise
The error is not handled p496 .
7.2 Timers
The setTimeout() p497 and setInterval() p498 methods allow authors to schedule timer-based callbacks.
496
[Supplemental, NoInterfaceObject]
interface WindowTimers {
long setTimeout(in any handler, in optional any timeout, in any... args);
void clearTimeout(in long handle);
long setInterval(in any handler, in optional any timeout, in any... args);
void clearInterval(in long handle);
};
Window implements WindowTimers;
This box is non-normative. Implementation requirements are given below this box.
handle = window . setTimeout p497 ( handler [, timeout [, arguments ] ] )
Schedules a timeout to run handler after timeout milliseconds. Any arguments are passed straight
through to the handler.
handle = window . setTimeout p497 ( code [, timeout ] )
Schedules a timeout to compile and run code after timeout milliseconds.
window . clearTimeout p498 ( handle )
Cancels the timeout set with setTimeout() p497 identified by handle.
handle = window . setInterval p498 ( handler [, timeout [, arguments ] ] )
Schedules a timeout to run handler every timeout milliseconds. Any arguments are passed straight
through to the handler.
handle = window . setInterval p498 ( code [, timeout ] )
Schedules a timeout to compile and run code every timeout milliseconds.
window . clearInterval p498 ( handle )
Cancels the timeout set with setInterval() p498 identified by handle.
Note: This API does not guarantee that timers will fire exactly on schedule. Delays due to CPU
load, other tasks, etc, are to be expected.
Note: The WindowTimers p497 interface adds to the Window p443 interface and the WorkerUtils
interface (part of Web Workers).
Each object that implements the WindowTimers p497 interface has a list of active timeouts and a list of active
intervals. Each entry in these lists is identified by a number, which must be unique within its list for the lifetime
of the object that implements the WindowTimers p497 interface.
The setTimeout() method must run the following steps:
1.
Let handle be a user-agent-defined integer that is greater than zero that will identify the timeout to be
set by this call.
2.
Add an entry to the list of active timeouts p497 for handle.
3.
Get the timed task p498 handle in the list of active timeouts p497 , and let task be the result.
4.
Get the timeout p499 , and let timeout be the result.
5.
If the currently running task p489 is a task that was created by the setTimeout() p497 method, and timeout
is less than 4, then increase timeout to 4.
6.
Return handle, and then continue running this algorithm asynchronously.
7.
If the method context p498 is a Window p443 object, wait until the Document p31 associated with the method
context p498 has been fully active p440 for a further timeout milliseconds (not necessarily consecutively).
Otherwise, if the method context p498 is a WorkerUtils object, wait until timeout milliseconds have
passed with the worker not suspended (not necessarily consecutively).
Otherwise, act as described in the specification that defines that the WindowTimers p497 interface is
implemented by some other object.
497
8.
Wait until any invocations of this algorithm started before this one whose timeout is equal to or less than
this one's have completed.
9.
Queue p490 the task task p489 .
The clearTimeout() method must clear the entry identified as handle from the list of active timeouts p497 of the
WindowTimers p497 object on which the method was invoked, where handle is the argument passed to the method.
The setInterval() method must run the following steps:
1.
Let handle be a user-agent-defined integer that is greater than zero that will identify the interval to be
set by this call.
2.
Add an entry to the list of active intervals p497 for handle.
3.
Get the timed task p498 handle in the list of active intervals p497 , and let task be the result.
4.
Get the timeout p499 , and let timeout be the result.
5.
If timeout is less than 10, then increase timeout to 10.
6.
Return handle, and then continue running this algorithm asynchronously.
7.
Wait: If the method context p498 is a Window p443 object, wait until the Document p31 associated with the
method context p498 has been fully active p440 for a further interval milliseconds (not necessarily
consecutively).
Otherwise, if the method context p498 is a WorkerUtils object, wait until interval milliseconds have
passed with the worker not suspended (not necessarily consecutively).
Otherwise, act as described in the specification that defines that the WindowTimers p497 interface is
implemented by some other object.
8.
Queue p490 the task task p489 .
9.
Return to the step labeled wait.
The clearInterval() method must clear the entry identified as handle from the list of active intervals p497 of the
WindowTimers p497 object on which the method was invoked, where handle is the argument passed to the method.
The method context, when referenced by the algorithms in this section, is the object on which the method for
which the algorithm is running is implemented (a Window p443 or WorkerUtils object).
When the above methods are invoked and try to get the timed task handle in list list, they must run the
following steps:
1.
If the first argument to the invoked method is an object that has an internal [[Call]] method, then return
a task p489 that checks if the entry for handle in list has been cleared, and if it has not, calls the
aforementioned [[Call]] method with as its arguments the third and subsequent arguments to the
invoked method (if any), and abort these steps.
Otherwise, continue with the remaining steps.
2.
Apply the ToString() abstract operation to the first argument to the method, and let script source be the
result. [ECMA262] p701
3.
Let script language be JavaScript.
4.
If the method context p498 is a Window p443 object, let global object be the method context p498 , let browsing
context be the browsing context p439 with which global object is associated, let character encoding be the
character encoding p75 of the Document p31 associated with global object (this is a reference, not a
copy p488 ), and let base URL be the base URL p52 of the Document p31 associated with global object (this is a
reference, not a copy p488 ).
Otherwise, if the method context p498 is a WorkerUtils object, let global object, browsing context,
document, character encoding, and base URL be the script's global object p487 , script's browsing
context p488 , script's document p488 , script's URL character encoding p488 , and script's base URL p488
(respectively) of the script p487 that the run a worker algorithm created when it created the method
context p498 .
Otherwise, act as described in the specification that defines that the WindowTimers p497 interface is
implemented by some other object.
498
5.
Return a task p489 that checks if the entry for handle in list has been cleared, and if it has not, creates a
script p488 using script source as the script source, scripting language as the scripting language, global
object as the global object, browsing context as the browsing context, document as the document,
character encoding as the URL character encoding, and base URL as the base URL.
When the above methods are to get the timeout, they must run the following steps:
1.
Let timeout be the second argument to the method, or zero if the argument was omitted.
2.
Apply the ToString() abstract operation to timeout, and let timeout be the result. [ECMA262] p701
3.
Apply the ToNumber() abstract operation to timeout, and let timeout be the result. [ECMA262] p701
4.
If timeout is an Infinity value, a Not-a-Number (NaN) value, or negative, let timeout be zero.
5.
Round timeout down to the nearest integer, and let timeout be the result.
6.
Return timeout.
The task source p490 for these tasks p489 is the timer task source.
7.3 User prompts
7.3.1 Simple dialogs
This box is non-normative. Implementation requirements are given below this box.
window . alert
p499
(message)
Displays a modal alert with the given message, and waits for the user to dismiss it.
A call to the navigator.yieldForStorageUpdates() p507 method is implied when this method is
invoked.
result = window . confirm p499 (message)
Displays a modal OK/Cancel prompt with the given message, waits for the user to dismiss it, and
returns true if the user clicks OK and false if the user clicks Cancel.
A call to the navigator.yieldForStorageUpdates() p507 method is implied when this method is
invoked.
result = window . prompt p499 (message [, default] )
Displays a modal text field prompt with the given message, waits for the user to dismiss it, and returns
the value that the user entered. If the user cancels the prompt, then returns null instead. If the second
argument is present, then the given value is used as a default.
A call to the navigator.yieldForStorageUpdates() p507 method is implied when this method is
invoked.
The alert(message) method, when invoked, must release the storage mutex p490 and show the given message to
the user. The user agent may make the method wait for the user to acknowledge the message before returning; if
so, the user agent must pause p491 while the method is waiting.
The confirm(message) method, when invoked, must release the storage mutex p490 and show the given message
to the user, and ask the user to respond with a positive or negative response. The user agent must then pause p491
as the method waits for the user's response. If the user responds positively, the method must return true, and if
the user responds negatively, the method must return false.
The prompt(message, default) method, when invoked, must release the storage mutex p490 , show the given
message to the user, and ask the user to either respond with a string value or abort. The user agent must then
pause p491 as the method waits for the user's response. The second argument is optional. If the second argument
(default) is present, then the response must be defaulted to the value given by default. If the user aborts, then the
method must return null; otherwise, the method must return the string that the user responded with.
7.3.2 Printing
This box is non-normative. Implementation requirements are given below this box.
499
window . print p500 ()
Prompts the user to print the page.
A call to the navigator.yieldForStorageUpdates() p507 method is implied when this method is
invoked.
The print() method, when invoked, must run the printing steps p500 .
User agents should also run the printing steps p500 whenever the user asks for the opportunity to obtain a physical
form p659 (e.g. printed copy), or the representation of a physical form (e.g. PDF copy), of a document.
The printing steps are as follows:
1.
The user agent may display a message to the user and/or may abort these steps.
For instance, a kiosk browser could silently ignore any invocations of the print() p500 method.
For instance, a browser on a mobile device could detect that there are no printers in the vicinity
and display a message saying so before continuing to offer a "save to PDF" option.
2.
The user agent must fire a simple event p496 named beforeprint at the Window p443 object of the
Document p31 that is being printed, as well as any nested browsing contexts p439 in it.
The beforeprint event can be used to annotate the printed copy, for instance adding the time at
which the document was printed.
3.
The user agent must release the storage mutex p490 .
4.
The user agent should offer the user the opportunity to obtain a physical form p659 (or the representation
of a physical form) of the document. The user agent may wait for the user to either accept or decline
before returning; if so, the user agent must pause p491 while the method is waiting. Even if the user agent
doesn't wait at this point, the user agent must use the state of the relevant documents as they are at
this point in the algorithm if and when it eventually creates the alternate form.
5.
The user agent must fire a simple event p496 named afterprint at the Window p443 object of the
Document p31 that is being printed, as well as any nested browsing contexts p439 in it.
The afterprint event can be used to revert annotations added in the earlier event, as well as
showing post-printing UI. For instance, if a page is walking the user through the steps of applying
for a home loan, the script could automatically advance to the next step after having printed a
form or other.
7.3.3 Dialogs implemented using separate documents
This box is non-normative. Implementation requirements are given below this box.
result = window . showModalDialog p500 (url [, argument] )
Prompts the user with the given page, waits for that page to close, and returns the return value.
A call to the navigator.yieldForStorageUpdates() p507 method is implied when this method is
invoked.
The showModalDialog(url, argument) method, when invoked, must cause the user agent to run the following
steps:
1.
Resolve p51 url relative to the entry script p441 's base URL p488 .
If this fails, then throw a SYNTAX_ERR p70 exception and abort these steps.
2.
Release the storage mutex p490 .
3.
If the user agent is configured such that this invocation of showModalDialog() p500 is somehow disabled,
then return the empty string and abort these steps.
Note: User agents are expected to disable this method in certain cases to avoid user
annoyance (e.g. as part of their popup blocker feature). For instance, a user agent
could require that a site be white-listed before enabling this method, or the user
agent could be configured to only allow one modal dialog at a time.
500
4.
Let the list of background browsing contexts be a list of all the browsing contexts that:
•
are part of the same unit of related browsing contexts p441 as the browsing context of the
Window p443 object on which the showModalDialog() p500 method was called, and that
•
have an active document p439 whose origin p449 is the same p451 as the origin p449 of the script p487
that called the showModalDialog() p500 method at the time the method was called,
...as well as any browsing contexts that are nested inside any of the browsing contexts matching those
conditions.
5.
Disable the user interface for all the browsing contexts in the list of background browsing contexts. This
should prevent the user from navigating those browsing contexts, causing events to be sent to those
browsing context, or editing any content in those browsing contexts. However, it does not prevent those
browsing contexts from receiving events from sources other than the user, from running scripts, from
running animations, and so forth.
6.
Create a new auxiliary browsing context p440 , with the opener browsing context p441 being the browsing
context of the Window p443 object on which the showModalDialog() p500 method was called. The new
auxiliary browsing context has no name.
Note: This browsing context p439 's Document p31 s' Window p443 objects all implement the
WindowModal p501 interface.
7.
Let the dialog arguments p501 of the new browsing context be set to the value of argument, or the
'undefined' value if the argument was omitted.
8.
Let the dialog arguments' origin p501 be the origin p449 of the script p487 that called the
showModalDialog() p500 method.
9.
Navigate p459 the new browsing context p439 to the absolute URL p52 that resulted from resolving p51 url
earlier, with replacement enabled p466 , and with the browsing context p488 of the script p487 that invoked the
method as the source browsing context p459 .
10.
Spin the event loop p490 until the new browsing context p439 is closed. (The user agent must allow the user
to indicate that the browsing context p439 is to be closed.)
11.
Reenable the user interface for all the browsing contexts in the list of background browsing contexts.
12.
Return the auxiliary browsing context p440 's return value p502 .
The Window p443 objects of Document p31 s hosted by browsing contexts p439 created by the above algorithm must all
have the WindowModal p501 interface added to their Window p443 interface:
[Supplemental, NoInterfaceObject] interface WindowModal {
readonly attribute any dialogArguments;
attribute DOMString returnValue;
};
This box is non-normative. Implementation requirements are given below this box.
window . dialogArguments p501
Returns the argument argument that was passed to the showModalDialog() p500 method.
window . returnValue p502 [ = value ]
Returns the current return value for the window.
Can be set, to change the value that will be returned by the showModalDialog() p500 method.
Such browsing contexts have associated dialog arguments, which are stored along with the dialog arguments'
origin. These values are set by the showModalDialog() p500 method in the algorithm above, when the browsing
context is created, based on the arguments provided to the method.
The dialogArguments IDL attribute, on getting, must check whether its browsing context's active document p439 's
origin p449 is the same p451 as the dialog arguments' origin p501 . If it is, then the browsing context's dialog
arguments p501 must be returned unchanged. Otherwise, if the dialog arguments p501 are an object, then the empty
string must be returned, and if the dialog arguments p501 are not an object, then the stringification of the dialog
arguments p501 must be returned.
501
These browsing contexts also have an associated return value. The return value p502 of a browsing context must
be initialized to the empty string when the browsing context is created.
The returnValue IDL attribute, on getting, must return the return value p502 of its browsing context, and on setting,
must set the return value p502 to the given new value.
Note: The window.close() p446 method can be used to close the browsing context.
7.4 System state and capabilities
The navigator attribute of the Window p443 interface must return an instance of the Navigator p502 interface, which
represents the identity and state of the user agent (the client), and allows Web pages to register themselves as
potential protocol and content handlers:
interface Navigator {
// objects implementing this interface also implement the interfaces given below
};
Navigator implements NavigatorID;
Navigator implements NavigatorOnLine;
Navigator implements NavigatorAbilities;
[Supplemental, NoInterfaceObject]
interface NavigatorID {
readonly attribute DOMString appName;
readonly attribute DOMString appVersion;
readonly attribute DOMString platform;
readonly attribute DOMString userAgent;
};
[Supplemental, NoInterfaceObject]
interface NavigatorOnLine {
readonly attribute boolean onLine;
};
[Supplemental, NoInterfaceObject]
interface NavigatorAbilities {
// content handler registration
void registerProtocolHandler(in DOMString scheme, in DOMString url, in DOMString
title);
void registerContentHandler(in DOMString mimeType, in DOMString url, in DOMString
title);
void yieldForStorageUpdates();
};
These interfaces are defined separately so that other specifications can re-use parts of the Navigator p502
interface.
7.4.1 Client identification
In certain cases, despite the best efforts of the entire industry, Web browsers have bugs and limitations that Web
authors are forced to work around.
This section defines a collection of attributes that can be used to determine, from script, the kind of user agent in
use, in order to work around these issues.
Client detection should always be limited to detecting known current versions; future versions and unknown
versions should always be assumed to be fully compliant.
This box is non-normative. Implementation requirements are given below this box.
window . navigator p502 . appName p503
Returns the name of the browser.
window . navigator p502 . appVersion p503
Returns the version of the browser.
502
window . navigator p502 . platform p503
Returns the name of the platform.
window . navigator p502 . userAgent p503
Returns the complete User-Agent header.
appName
Must return either the string "Netscape" or the full name of the browser, e.g. "Mellblom Browsernator".
appVersion
Must return either the string "4.0" or a string representing the version of the browser in detail, e.g. "1.0
(VMS; en-US) Mellblomenator/9000".
platform
Must return either the empty string or a string representing the platform on which the browser is executing,
e.g. "MacIntel", "Win32", "FreeBSD i386", "WebTV OS".
userAgent
Must return the string used for the value of the "User-Agent" header in HTTP requests, or the empty string if
no such header is ever sent.
7.4.2 Custom scheme and content handlers
The registerProtocolHandler() method allows Web sites to register themselves as possible handlers for
particular schemes. For example, an online telephone messaging service could register itself as a handler of the
sms: scheme ([RFC5724] p703 ), so that if the user clicks on such a link, he is given the opportunity to use that Web
site. Analogously, the registerContentHandler() method allows Web sites to register themselves as possible
handlers for content in a particular MIME type p26 . For example, the same online telephone messaging service
could register itself as a handler for text/directory files ([RFC2425] p703 ), so that if the user has no native
application capable of handling vCards ([RFC2426] p703 ), his Web browser can instead suggest he use that site to
view contact information stored on vCards that he opens.
This box is non-normative. Implementation requirements are given below this box.
window . navigator
p502
. registerProtocolHandler p503 (scheme, url, title)
window . navigator p502 . registerContentHandler p503 (mimeType, url, title)
Registers a handler for the given scheme or content type, at the given URL, with the given title.
The string "%s" in the URL is used as a placeholder for where to put the URL of the content to be
handled.
Throws a SECURITY_ERR p70 exception if the user agent blocks the registration (this might happen if
trying to register as a handler for "http", for instance).
Throws a SYNTAX_ERR p70 if the "%s" string is missing in the URL.
User agents may, within the constraints described in this section, do whatever they like when the methods are
called. A UA could, for instance, prompt the user and offer the user the opportunity to add the site to a shortlist of
handlers, or make the handlers his default, or cancel the request. UAs could provide such a UI through modal UI or
through a non-modal transient notification interface. UAs could also simply silently collect the information,
providing it only when relevant to the user.
User agents should keep track of which sites have registered handlers (even if the user has declined such
registrations) so that the user is not repeatedly prompted with the same request.
The arguments to the methods have the following meanings and corresponding implementation requirements:
protocol (registerProtocolHandler() p503 only)
A scheme, such as ftp or sms. The scheme must be compared in an ASCII case-insensitive p33 manner by
user agents for the purposes of comparing with the scheme part of URLs that they consider against the list of
registered handlers.
The scheme value, if it contains a colon (as in "ftp:"), will never match anything, since schemes don't
contain colons.
Note: This feature is not intended to be used with non-standard protocols.
503
mimeType (registerContentHandler() p503 only)
A MIME type p26 , such as model/vnd.flatland.3dml or application/vnd.google-earth.kml+xml. The MIME
type p26 must be compared in an ASCII case-insensitive p33 manner by user agents for the purposes of
comparing with MIME types of documents that they consider against the list of registered handlers.
User agents must compare the given values only to the MIME type/subtype parts of content types, not to the
complete type including parameters. Thus, if mimeType values passed to this method include characters
such as commas or whitespace, or include MIME parameters, then the handler being registered will never be
used.
Note: The type is compared to the MIME type p26 used by the user agent after the sniffing
algorithms have been applied.
url
A string used to build the URL p51 of the page that will handle the requests.
When the user agent uses this URL, it must replace the first occurrence of the exact literal string "%s" with an
escaped version of the absolute URL p52 of the content in question (as defined below), then resolve p51 the
resulting URL, relative to the base URL p488 of the entry script p441 at the time the
registerContentHandler() p503 or registerProtocolHandler() p503 methods were invoked, and then
navigate p459 an appropriate browsing context p439 to the resulting URL using the GET method (or equivalent p56
for non-HTTP URLs).
To get the escaped version of the absolute URL p52 of the content in question, the user agent must replace
every character in that absolute URL p52 that doesn't match the production defined in RFC 3986 by
the percent-encoded form of that character. [RFC3986] p703
If the user had visited a site at http://example.com/ that made the following call:
navigator.registerContentHandler('application/x-soup', 'soup?url=%s', 'SoupWeb™')
...and then, much later, while visiting http://www.example.net/, clicked on a link such as:
Download our Chicken Kïwi soup!
...then, assuming this chickenkïwi.soup file was served with the MIME type p26 application/x-soup,
the UA might navigate to the following URL:
http://example.com/soup?url=http://www.example.net/chickenk%C3%AFwi.soup
This site could then fetch the chickenkïwi.soup file and do whatever it is that it does with soup
(synthesize it and ship it to the user, or whatever).
title
A descriptive title of the handler, which the UA might use to remind the user what the site in question is.
User agents should raise SECURITY_ERR p70 exceptions if the methods are called with scheme or mimeType values
that the UA deems to be "privileged". For example, a site attempting to register a handler for http URLs or text/
html p678 content in a Web browser would likely cause an exception to be raised.
User agents must raise a SYNTAX_ERR p70 exception if the url argument passed to one of these methods does not
contain the exact literal string "%s", or if resolving p51 the url argument with the first occurrence of the string "%s"
removed, relative to the entry script p441 's base URL p488 , is not successful.
User agents must not raise any other exceptions (other than binding-specific exceptions, such as for an incorrect
number of arguments in an JavaScript implementation).
This section does not define how the pages registered by these methods are used, beyond the requirements on
how to process the url value (see above). To some extent, the processing model for navigating across
documents p459 defines some cases where these methods are relevant, but in general UAs may use this information
wherever they would otherwise consider handing content to native plugins or helper applications.
UAs must not use registered content handlers to handle content that was returned as part of a non-GET
transaction (or rather, as part of any non-idempotent transaction), as the remote site would not be able to fetch
the same data.
7.4.2.1 Security and privacy
These mechanisms can introduce a number of concerns, in particular privacy concerns.
Hijacking all Web usage. User agents should not allow schemes that are key to its normal operation, such as
http or https, to be rerouted through third-party sites. This would allow a user's activities to be trivially tracked,
and would allow user information, even in secure connections, to be collected.
504
Hijacking defaults. It is strongly recommended that user agents do not automatically change any defaults, as
this could lead the user to send data to remote hosts that the user is not expecting. New handlers registering
themselves should never automatically cause those sites to be used.
Registration spamming. User agents should consider the possibility that a site will attempt to register a large
number of handlers, possibly from multiple domains (e.g. by redirecting through a series of pages each on a
different domain, and each registering a handler for video/mpeg — analogous practices abusing other Web
browser features have been used by pornography Web sites for many years). User agents should gracefully handle
such hostile attempts, protecting the user.
Misleading titles. User agents should not rely wholly on the title argument to the methods when presenting the
registered handlers to the user, since sites could easily lie. For example, a site hostile.example.net could claim
that it was registering the "Cuddly Bear Happy Content Handler". User agents should therefore use the handler's
domain in any UI along with any title.
Hostile handler metadata. User agents should protect against typical attacks against strings embedded in their
interface, for example ensuring that markup or escape characters in such strings are not executed, that null bytes
are properly handled, that over-long strings do not cause crashes or buffer overruns, and so forth.
Leaking Intranet URLs. The mechanism described in this section can result in secret Intranet URLs being leaked,
in the following manner:
1.
The user registers a third-party content handler as the default handler for a content type.
2.
The user then browses his corporate Intranet site and accesses a document that uses that content type.
3.
The user agent contacts the third party and hands the third party the URL to the Intranet content.
No actual confidential file data is leaked in this manner, but the URLs themselves could contain confidential
information. For example, the URL could be http://www.corp.example.com/upcoming-aquisitions/thesample-company.egf, which might tell the third party that Example Corporation is intending to merge with The
Sample Company. Implementors might wish to consider allowing administrators to disable this feature for certain
subdomains, content types, or schemes.
Leaking secure URLs. User agents should not send HTTPS URLs to third-party sites registered as content
handlers, in the same way that user agents do not send Referer (sic) HTTP headers from secure sites to thirdparty sites.
Leaking credentials. User agents must never send username or password information in the URLs that are
escaped and included sent to the handler sites. User agents may even avoid attempting to pass to Web-based
handlers the URLs of resources that are known to require authentication to access, as such sites would be unable
to access the resources in question without prompting the user for credentials themselves (a practice that would
require the user to know whether to trust the third-party handler, a decision many users are unable to make or
even understand).
7.4.2.2 Sample user interface
This section is non-normative.
A simple implementation of this feature for a desktop Web browser might work as follows.
The registerContentHandler() p503 method could display a modal dialog box:
505
In this dialog box, "Kittens at work" is the title of the page that invoked the method, "http://kittens.example.org/"
is the URL of that page, "application/x-meowmeow" is the string that was passed to the
registerContentHandler() p503 method as its first argument (mimeType), "http://kittens.example.org/?show=%s"
was the second argument (url), and "Kittens-at-work displayer" was the third argument (title).
If the user clicks the Cancel button, then nothing further happens. If the user clicks the "Trust" button, then the
handler is remembered.
When the user then attempts to fetch a URL that uses the "application/x-meowmeow" MIME type p26 , then it might
display a dialog as follows:
506
In this dialog, the third option is the one that was primed by the site registering itself earlier.
If the user does select that option, then the browser, in accordance with the requirements described in the
previous two sections, will redirect the user to "http://kittens.example.org/?show=data%3Aapplication/xmeowmeow;base64,S2l0dGVucyBhcmUgdGhlIGN1dGVzdCE%253D".
The registerProtocolHandler() p503 method would work equivalently, but for schemes instead of unknown
content types.
7.4.3 Manually releasing the storage mutex
This box is non-normative. Implementation requirements are given below this box.
window . navigator
p502
. yieldForStorageUpdates p507 ()
If a script uses the document.cookie p74 API, or the localStorage API, the browser will block other
scripts from accessing cookies or storage until the first script finishes. [WEBSTORAGE] p704
Calling the navigator.yieldForStorageUpdates() p507 method tells the user agent to unblock any
other scripts that may be blocked, even though the script hasn't returned.
Values of cookies and items in the Storage objects of localStorage attributes can change after
calling this method, whence its name. [WEBSTORAGE] p704
The yieldForStorageUpdates() method, when invoked, must, if the storage mutex p490 is owned by the event
loop p489 of the task p489 that resulted in the method being called, release the storage mutex p490 so that it is once
again free. Otherwise, it must do nothing.
507
8 User interaction
This section describes various features that allow authors to enable users to edit documents and parts of
documents interactively.
8.1 The hidden attribute
All HTML elements p26 may have the hidden p508 content attribute set. The hidden p508 attribute is a boolean
attribute p34 . When specified on an element, it indicates that the element is not yet, or is no longer, relevant. User
agents should not render elements that have the hidden p508 attribute specified.
In the following skeletal example, the attribute is used to hide the Web game's main screen until the user
logs in:
The Example Game
The hidden p508 attribute must not be used to hide content that could legitimately be shown in another
presentation. For example, it is incorrect to use hidden p508 to hide panels in a tabbed dialog, because the tabbed
interface is merely a kind of overflow presentation — one could equally well just show all the form controls in one
big page with a scrollbar. It is similarly incorrect to use this attribute to hide content just from one presentation —
if something is marked hidden p508 , it is hidden from all presentations, including, for instance, screen readers.
Elements that are not hidden p508 should not link to or refer to elements that are hidden p508 .
For example, it would be incorrect to use the href p383 attribute to link to a section marked with the
hidden p508 attribute. If the content is not applicable or relevant, then there is no reason to link to it.
It would similarly be incorrect to use the ARIA aria-describedby attribute to refer to descriptions that are
themselves hidden p508 . Hiding a section means that it is not applicable or relevant to anyone at the current
time, so clearly it cannot be a valid description of content the user can interact with.
Elements in a section hidden by the hidden p508 attribute are still active, e.g. scripts and form controls in such
sections still execute and submit respectively. Only their presentation to the user changes.
The hidden IDL attribute must reflect p57 the content attribute of the same name.
8.2 Activation
This box is non-normative. Implementation requirements are given below this box.
element . click
p508
()
Acts as if the element was clicked.
Each element has a click in progress flag, initially set to false.
The click() method must run these steps:
508
1.
If the element's click in progress flag is set to true, then abort these steps.
2.
Set the click in progress flag on the element to true.
3.
If the element has a defined activation behavior p93 , run synthetic click activation steps p92 on the
element. Otherwise, fire a click event p496 at the element.
4.
Set the click in progress flag on the element to false.
8.3 Scrolling elements into view
This box is non-normative. Implementation requirements are given below this box.
element . scrollIntoView p509 ( [ top ] )
Scrolls the element into view. If the top argument is true, then the element will be scrolled to the top
of the viewport, otherwise it'll be scrolled to the bottom. The default is the top.
The scrollIntoView([top]) method, when called, must cause the element on which the method was called to
have the attention of the user called to it.
Note: In a speech browser, this could happen by having the current playback position move to
the start of the given element.
If the element in question cannot be brought to the user's attention, e.g. because it is hidden p508 , or is not being
rendered p638 , then the user agent must do nothing instead.
In visual user agents, if the argument is present and has the value false, the user agent should scroll the element
into view such that both the bottom and the top of the element are in the viewport, with the bottom of the
element aligned with the bottom of the viewport. If it isn't possible to show the entire element in that way, or if the
argument is omitted or is true, then the user agent should instead align the top of the element with the top of the
viewport. If the entire scrollable part of the content is visible all at once (e.g. if a page is shorter than the
viewport), then the user agent should not scroll anything. Visual user agents should further scroll horizontally as
necessary to bring the element to the attention of the user.
Non-visual user agents may ignore the argument, or may treat it in some media-specific manner most useful to
the user.
8.4 Focus
When an element is focused, key events received by the document must be targeted at that element. There may
be no element focused; when no element is focused, key events received by the document must be targeted at
the body element p76 .
User agents may track focus for each browsing context p439 or Document p31 individually, or may support only one
focused element per top-level browsing context p439 — user agents should follow platform conventions in this
regard.
Which elements within a top-level browsing context p439 currently have focus must be independent of whether or
not the top-level browsing context p439 itself has the system focus.
Note: When an element is focused, the element matches the CSS :focus pseudo-class.
8.4.1 Sequential focus navigation
The tabindex content attribute specifies whether the element is focusable, whether it can be reached using
sequential focus navigation, and the relative order of the element for the purposes of sequential focus navigation.
The name "tab index" comes from the common use of the "tab" key to navigate through the focusable elements.
The term "tabbing" refers to moving forward through the focusable elements that can be reached using sequential
focus navigation.
The tabindex p509 attribute, if specified, must have a value that is a valid integer p35 .
If the attribute is specified, it must be parsed using the rules for parsing integers p35 . The attribute's values have
the following meanings:
If the attribute is omitted or parsing the value returns an error
The user agent should follow platform conventions to determine if the element is to be focusable and, if so,
whether the element can be reached using sequential focus navigation, and if so, what its relative order
should be.
509
If the value is a negative integer
The user agent must allow the element to be focused, but should not allow the element to be reached using
sequential focus navigation.
If the value is a zero
The user agent must allow the element to be focused, should allow the element to be reached using
sequential focus navigation, and should follow platform conventions to determine the element's relative
order.
If the value is greater than zero
The user agent must allow the element to be focused, should allow the element to be reached using
sequential focus navigation, and should place the element in the sequential focus navigation order so that it
is:
•
before any focusable element whose tabindex p509 attribute has been omitted or whose value,
when parsed, returns an error,
•
before any focusable element whose tabindex p509 attribute has a value equal to or less than zero,
•
after any element whose tabindex p509 attribute has a value greater than zero but less than the
value of the tabindex p509 attribute on the element,
•
after any element whose tabindex p509 attribute has a value equal to the value of the tabindex p509
attribute on the element but that is earlier in the document in tree order p27 than the element,
•
before any element whose tabindex p509 attribute has a value equal to the value of the
tabindex p509 attribute on the element but that is later in the document in tree order p27 than the
element, and
•
before any element whose tabindex p509 attribute has a value greater than the value of the
tabindex p509 attribute on the element.
An element is specially focusable if the tabindex p509 attribute's definition above defines the element to be
focusable.
An element that is specially focusable p510 but does not otherwise have an activation behavior p93 defined has an
activation behavior p93 that does nothing.
Note: This means that an element that is only focusable because of its tabindex p509 attribute
will fire a click p31 event in response to a non-mouse activation (e.g. hitting the "enter" key
while the element is focused).
The tabIndex IDL attribute must reflect p57 the value of the tabindex p509 content attribute. If the attribute is not
present, or parsing its value returns an error, then the IDL attribute must return 0 for elements that are focusable
and −1 for elements that are not focusable.
8.4.2 Focus management
An element is focusable if the user agent's default behavior allows it to be focusable or if the element is specially
focusable p510 , but only if the element is either being rendered p638 or is a descendant of a canvas p238 element that
represents p638 embedded content p92 .
User agents should make the following elements focusable p510 , unless platform conventions dictate otherwise:
510
•
a p160 elements that have an href p383 attribute
•
link p109 elements that have an href p109 attribute
•
button p332 elements that are not disabled p354
•
input p303 elements whose type p304 attribute are not in the Hidden p307 state and that are not disabled p354
•
select p334 elements that are not disabled p354
•
textarea p341 elements that are not disabled p354
•
command p371 elements that do not have a disabled p371 attribute
•
Elements with a draggable p531 attribute set, if that would enable the user agent to allow the user to
begin a drag operations for those elements without the use of a pointing device
In addition, each shape that is generated for an area p266 element should be focusable p510 , unless platform
conventions dictate otherwise. (A single area p266 element can correspond to multiple shapes, since image maps
can be reused with multiple images on a page.)
The focusing steps are as follows:
1.
If focusing the element will remove the focus from another element, then run the unfocusing steps p511
for that element.
2.
Make the element the currently focused element in its top-level browsing context p439 .
Some elements, most notably area p266 , can correspond to more than one distinct focusable area. If a
particular area was indicated when the element was focused, then that is the area that must get focus;
otherwise, e.g. when using the focus() p512 method, the first such region in tree order is the one that
must be focused.
3.
Fire a simple event p496 named focus at the element.
User agents must synchronously run the focusing steps p511 for an element whenever the user moves the focus to a
focusable p510 element.
The unfocusing steps are as follows:
1.
If the element is an input p303 element, and the change p332 event applies to the element, and the
element does not have a defined activation behavior p93 , and the user has changed the element's
value p354 or its list of selected files p320 while the control was focused without committing that change,
then fire a simple event p496 that bubbles named change at the element, then broadcast formchange
events p366 at the element's form owner p353 .
2.
Unfocus the element.
3.
Fire a simple event p496 named blur at the element.
When an element that is focused stops being a focusable p510 element, or stops being focused without another
element being explicitly focused in its stead, the user agent should synchronously run the focusing steps p511 for
the body element p76 , if there is one; if there is not, then the user agent should synchronously run the unfocusing
steps p511 for the affected element only.
For example, this might happen because the element is removed from its Document p31 , or has a hidden p508
attribute added. It would also happen to an input p303 element when the element gets disabled p354 .
8.4.3 Document-level focus APIs
This box is non-normative. Implementation requirements are given below this box.
document . activeElement p511
Returns the currently focused element.
document . hasFocus p511 ()
Returns true if the document has focus; otherwise, returns false.
window . focus p511 ()
Focuses the window. Use of this method is discouraged. Allow the user to control window focus
instead.
window . blur p512 ()
Unfocuses the window. Use of this method is discouraged. Allow the user to control window focus
instead.
The activeElement attribute on HTMLDocument p71 objects must return the element in the document that is
focused. If no element in the Document p31 is focused, this must return the body element p76 .
The hasFocus() method on HTMLDocument p71 objects must return true if the document's browsing context p439 is
focused, and all its ancestor browsing contexts p440 are also focused, and the top-level browsing context p439 has the
system focus.
The focus() method on the Window p443 object, when invoked, provides a hint to the user agent that the script
believes the user might be interested in the contents of the browsing context p439 of the Window p443 object on which
the method was invoked.
511
User agents are encouraged to have this focus() p511 method trigger some kind of notification.
The blur() method on the Window p443 object, when invoked, provides a hint to the user agent that the script
believes the user probably is not currently interested in the contents of the browsing context p439 of the Window p443
object on which the method was invoked, but that the contents might become interesting again in the future.
User agents are encouraged to ignore calls to this blur() p512 method entirely.
Note: Historically the focus() p512 and blur() p512 methods actually affected the system focus,
but hostile sites widely abuse this behavior to the user's detriment.
8.4.4 Element-level focus APIs
This box is non-normative. Implementation requirements are given below this box.
element . focus p512 ()
Focuses the element.
element . blur p512 ()
Unfocuses the element. Use of this method is discouraged. Focus another element instead.
Do not use this method to hide the focus ring if you find the focus ring unsightly. Instead, use a CSS
rule to override the 'outline' property.
For example, to hide the outline from links, you could use:
:link:focus, :visited:focus { outline: none; }
The focus() method, when invoked, must run the following algorithm:
1.
If the element is marked as locked for focus p512 , then abort these steps.
2.
If the element is not focusable p510 , then abort these steps.
3.
Mark the element as locked for focus.
4.
If the element is not already focused, run the focusing steps p511 for the element.
5.
Unmark the element as locked for focus p512 .
The blur() method, when invoked, should run the focusing steps p511 for the body element p76 , if there is one; if
there is not, then it should run the unfocusing steps p511 for the element on which the method was called instead.
User agents may selectively or uniformly ignore calls to this method for usability reasons.
For example, if the blur() p512 method is unwisely being used to remove the focus ring for aesthetics
reasons, the page would become unusable by keyboard users. Ignoring calls to this method would thus
allow keyboard users to interact with the page.
8.5 The accesskey attribute
All HTML elements p26 may have the accesskey p512 content attribute set. The accesskey p512 attribute's value is
used by the user agent as a guide for creating a keyboard shortcut that activates or focuses the element.
If specified, the value must be an ordered set of unique space-separated tokens p49 , each of which must be exactly
one Unicode code point in length.
An element's assigned access key is a key combination derived from the element's accesskey p512 content
attribute as follows:
1.
If the element has no accesskey p512 attribute, then skip to the fallback step below.
2.
Otherwise, the user agent must split the attribute's value on spaces p49 , and let keys be the resulting
tokens.
3.
For each value in keys in turn, in the order the tokens appeared in the attribute's value, run the following
substeps:
1.
512
If the value is not a string exactly one Unicode code point in length, then skip the remainder of
these steps for this value.
2.
If the value does not correspond to a key on the system's keyboard, then skip the remainder of
these steps for this value.
3.
If the user agent can find a combination of modifier keys that, with the key that corresponds to
the value given in the attribute, can be used as a shortcut key, then the user agent may
assign that combination of keys as the element's assigned access key p512 and abort these
steps.
4.
Fallback: Optionally, the user agent may assign a key combination of its choosing as the element's
assigned access key p512 and then abort these steps.
5.
If this step is reached, the element has no assigned access key p512 .
Once a user agent has selected and assigned an access key for an element, the user agent should not change the
element's assigned access key p512 unless the accesskey p512 content attribute is changed or the element is moved
to another Document p31 .
When the user presses the key combination corresponding to the assigned access key p512 for an element, if the
element defines a command p376 , and the command's Hidden State p376 facet is false (visible), and the command's
Disabled State p376 facet is also false (enabled), then the user agent must trigger the Action p376 of the command.
User agents may expose elements that have an accesskey p512 attribute in other ways as well, e.g. in a menu
displayed in response to a specific key combination.
The accessKey IDL attribute must reflect p57 the accesskey p512 content attribute.
The accessKeyLabel IDL attribute must return a string that represents the element's assigned access key p512 , if
any. If the element does not have one, then the IDL attribute must return the empty string.
In the following example, a variety of links are given with access keys so that keyboard users familiar with
the site can more quickly navigate to the relevant pages:
Activities |
Technical
Reports |
Site
Index |
About Consortium |
Contact
In the following example, the search field is given two possible access keys, "s" and "0" (in that order). A
user agent on a device with a full keyboard might pick Ctrl+Alt+S as the shortcut key, while a user agent
on a small device with just a numeric keypad might pick just the plain unadorned key 0:
In the following example, a button has possible access keys described. A script then tries to update the
button's label to advertise the key combination the user agent selected.
The cute girl likes the Oxford English Dictionary .
516
If a script invoked window.getSelection().toString(), the return value would be "the Oxford English".
8.6.2 APIs for the text field selections
The input p303 and textarea p341 elements define the following members in their DOM interfaces for handling their
text selection:
void select();
attribute unsigned long selectionStart;
attribute unsigned long selectionEnd;
void setSelectionRange(in unsigned long start, in unsigned long end);
These methods and attributes expose and control the selection of input p303 and textarea p341 text fields.
This box is non-normative. Implementation requirements are given below this box.
element . select p517 ()
Selects everything in the text field.
element . selectionStart [ = value ]
Returns the offset to the start of the selection.
Can be set, to change the start of the selection.
element . selectionEnd [ = value ]
Returns the offset to the end of the selection.
Can be set, to change the end of the selection.
element . setSelectionRange p517 (start, end)
Changes the selection to cover the given substring.
When these methods and attributes are used with input p303 elements while they don't apply, they must raise an
INVALID_STATE_ERR p70 exception. Otherwise, they must act as described below.
The select() method must cause the contents of the text field to be fully selected.
The selectionStart attribute must, on getting, return the offset (in logical order) to the character that
immediately follows the start of the selection. If there is no selection, then it must return the offset (in logical
order) to the character that immediately follows the text entry cursor.
On setting, it must act as if the setSelectionRange() p517 method had been called, with the new value as the first
argument, and the current value of the selectionEnd p517 attribute as the second argument, unless the current
value of the selectionEnd p517 is less than the new value, in which case the second argument must also be the
new value.
The selectionEnd attribute must, on getting, return the offset (in logical order) to the character that immediately
follows the end of the selection. If there is no selection, then it must return the offset (in logical order) to the
character that immediately follows the text entry cursor.
On setting, it must act as if the setSelectionRange() p517 method had been called, with the current value of the
selectionStart p517 attribute as the first argument, and new value as the second argument.
The setSelectionRange(start, end) method must set the selection of the text field to the sequence of
characters starting with the character at the startth position (in logical order) and ending with the character at the
(end-1)th position. Arguments greater than the length of the value in the text field must be treated as pointing at
the end of the text field. If end is less than or equal to start then the start of the selection and the end of the
selection must both be placed immediately before the character with offset end. In UAs where there is no concept
of an empty selection, this must set the cursor to be just before the character with offset end.
To obtain the currently selected text, the following JavaScript suffices:
var selectionText = control.value.substring(control.selectionStart,
control.selectionEnd);
...where control is the input p303 or textarea p341 element.
Characters with no visible rendering, such as U+200D ZERO WIDTH JOINER, still count as characters. Thus, for
instance, the selection can include just an invisible character, and the text insertion cursor can be placed to one
side or another of such a character.
517
8.7 The contenteditable p518 attribute
The contenteditable attribute is an enumerated attribute p34 whose keywords are the empty string, true, and
false. The empty string and the true keyword map to the true state. The false keyword maps to the false state.
In addition, there is a third state, the inherit state, which is the missing value default (and the invalid value
default).
The true state indicates that the element is editable. The inherit state indicates that the element is editable if its
parent is. The false state indicates that the element is not editable.
Specifically, if an HTML element p26 has a contenteditable p518 attribute set to the true state, or it has its
contenteditable p518 attribute set to the inherit state and if its nearest ancestor HTML element p26 with the
contenteditable p518 attribute set to a state other than the inherit state has its attribute set to the true state, or if
it and its ancestors all have their contenteditable p518 attribute set to the inherit state but the Document p31 has
designMode p520 enabled, then the UA must treat the element as editable (as described below).
Otherwise, either the HTML element p26 has a contenteditable p518 attribute set to the false state, or its
contenteditable p518 attribute is set to the inherit state and its nearest ancestor HTML element p26 with the
contenteditable p518 attribute set to a state other than the inherit state has its attribute set to the false state, or
all its ancestors have their contenteditable p518 attribute set to the inherit state and the Document p31 itself has
designMode p520 disabled; either way, the element is not editable.
This box is non-normative. Implementation requirements are given below this box.
element . contentEditable p518 [ = value ]
Returns "true", "false", or "inherit", based on the state of the contenteditable p518 attribute.
Can be set, to change that state.
Throws a SYNTAX_ERR p70 exception if the new value isn't one of those strings.
element . isContentEditable p518
Returns true if the element is editable; otherwise, returns false.
The contentEditable IDL attribute, on getting, must return the string "true" if the content attribute is set to the
true state, false" if the content attribute is set to the false state, and "inherit" otherwise. On setting, if the new
value is an ASCII case-insensitive p33 match for the string "inherit" then the content attribute must be removed, if
the new value is an ASCII case-insensitive p33 match for the string "true" then the content attribute must be set to
the string "true", if the new value is an ASCII case-insensitive p33 match for the string "false" then the content
attribute must be set to the string "false", and otherwise the attribute setter must raise a SYNTAX_ERR p70
exception.
The isContentEditable IDL attribute, on getting, must return true if the element is editable p518 , and false
otherwise.
If an element is editable p518 and its parent element is not, or if an element is editable p518 and it has no parent
element, then the element is an editing host. Editable elements can be nested. User agents must make editing
hosts focusable (which typically means they enter the tab order p509 ). An editing host can contain non-editable
sections, these are handled as described below. An editing host can contain non-editable sections that contain
further editing hosts.
When an editing host has focus, it must have a caret position that specifies where the current editing position is.
It may also have a selection p514 .
Note: How the caret and selection are represented depends entirely on the UA.
8.7.1 User editing actions
There are several actions that the user agent should allow the user to perform while the user is interacting with an
editing host. How exactly each action is triggered is not defined for every action, but when it is not defined,
suggested key bindings are provided to guide implementors.
Move the caret
User agents must allow users to move the caret to any position within an editing host, even into nested
editable elements. This could be triggered as the default action of keydown events with various key
identifiers and as the default action of mousedown events.
518
Change the selection
User agents must allow users to change the selection p514 within an editing host, even into nested editable
elements. User agents may prevent selections from being made in ways that cross from editable elements
into non-editable elements (e.g. by making each non-editable descendant atomically selectable, but not
allowing text selection within them). This could be triggered as the default action of keydown events with
various key identifiers and as the default action of mousedown events.
Insert text
This action must be triggered as the default action of a textInput event, and may be triggered by other
commands as well. It must cause the user agent to insert the specified text (given by the event object's data
attribute in the case of the textInput event) at the caret.
If the caret is positioned somewhere where phrasing content p91 is not allowed (e.g. inside an empty ol p152
element), then the user agent must not insert the text directly at the caret position. In such cases the
behavior is UA-dependent, but user agents must not, in response to a request to insert text, generate a DOM
that is less conformant than the DOM prior to the request.
User agents should allow users to insert new paragraphs into elements that contains only content other than
paragraphs.
For example, given the markup:
...the user agent should allow the user to insert p p148 elements before and after the dl p155 element, as
children of the section p133 element.
Break block
UAs should offer a way for the user to request that the current paragraph be broken at the caret, e.g. as the
default action of a keydown event whose identifier is the "Enter" key and that has no modifiers set.
The exact behavior is UA-dependent, but user agents must not, in response to a request to break a
paragraph, generate a DOM that is less conformant than the DOM prior to the request.
Insert a line separator
UAs should offer a way for the user to request an explicit line break at the caret position without breaking the
paragraph, e.g. as the default action of a keydown event whose identifier is the "Enter" key and that has a
shift modifier set. Line separators are typically found within a poem verse or an address. To insert a line
break, the user agent must insert a br p181 element.
If the caret is positioned somewhere where phrasing content p91 is not allowed (e.g. in an empty ol p152
element), then the user agent must not insert the br p181 element directly at the caret position. In such cases
the behavior is UA-dependent, but user agents must not, in response to a request to insert a line separator,
generate a DOM that is less conformant than the DOM prior to the request.
Delete
UAs should offer a way for the user to delete text and elements, including non-editable descendants, e.g. as
the default action of keydown events whose identifiers are "U+0008" or "U+007F".
Five edge cases in particular need to be considered carefully when implementing this feature: backspacing at
the start of an element, backspacing when the caret is immediately after an element, forward-deleting at the
end of an element, forward-deleting when the caret is immediately before an element, and deleting a
selection p514 whose start and end points do not share a common parent node.
In any case, the exact behavior is UA-dependent, but user agents must not, in response to a request to
delete text or an element, generate a DOM that is less conformant than the DOM prior to the request.
Insert, and wrap text in, semantic elements
UAs should offer the user the ability to mark text and paragraphs with semantics that HTML can express.
UAs should similarly offer a way for the user to insert empty semantic elements to subsequently fill by
entering text manually.
UAs should also offer a way to remove those semantics from marked up text, and to remove empty semantic
element that have been inserted.
In response to a request from a user to mark text up in italics, user agents should use the i p174 element to
represent the semantic. The em p162 element should be used only if the user agent is sure that the user means
to indicate stress emphasis.
519
In response to a request from a user to mark text up in bold, user agents should use the b p175 element to
represent the semantic. The strong p163 element should be used only if the user agent is sure that the user
means to indicate importance.
The exact behavior is UA-dependent, but user agents must not, in response to a request to wrap semantics
around some text or to insert or remove a semantic element, generate a DOM that is less conformant than
the DOM prior to the request.
Select and move non-editable elements nested inside editing hosts
UAs should offer a way for the user to move images and other non-editable parts around the content within
an editing host. This may be done using the drag and drop p522 mechanism. User agents must not, in
response to a request to move non-editable elements nested inside editing hosts, generate a DOM that is
less conformant than the DOM prior to the request.
Edit form controls nested inside editing hosts
When an editable p518 form control is edited, the changes must be reflected in both its current value and its
default value. For input p303 elements this means updating the defaultValue p307 IDL attribute as well as the
value p330 IDL attribute; for select p334 elements it means updating the option p339 elements'
defaultSelected p341 IDL attribute as well as the selected p341 IDL attribute; for textarea p341 elements this
means updating the defaultValue p344 IDL attribute as well as the value p344 IDL attribute. (Updating the
default* IDL attributes causes content attributes to be updated as well.)
User agents may perform several commands per user request; for example if the user selects a block of text and
hits Enter, the UA might interpret that as a request to delete the content of the selection p514 followed by a request
to break the paragraph at that position.
User agents may add DOM changes p532 entries to the undo transaction history p532 of the editing host p518 's
Document p31 object each time an action is triggered.
All of the actions defined above, whether triggered by the user or programmatically (e.g. by execCommand() p535
commands), must fire mutation events as appropriate.
8.7.2 Making entire documents editable
Documents have a designMode, which can be either enabled or disabled.
This box is non-normative. Implementation requirements are given below this box.
document . designMode p520 [ = value ]
Returns "on" if the document is editable, and "off" if it isn't.
Can be set, to change the document's current state.
The designMode p520 IDL attribute on the Document p31 object takes two values, "on" and "off". When it is set, the
new value must be compared in an ASCII case-insensitive p33 manner to these two values. If it matches the "on"
value, then designMode p520 must be enabled, and if it matches the "off" value, then designMode p520 must be
disabled. Other values must be ignored.
When designMode p520 is enabled, the IDL attribute must return the value "on", and when it is disabled, it must
return the value "off".
The last state set must persist until the document is destroyed or the state is changed. Initially, documents must
have their designMode p520 disabled.
8.8 Spelling and grammar checking
User agents can support the checking of spelling and grammar of editable text, either in form controls (such as
the value of textarea p341 elements), or in elements in an editing host p518 (using contenteditable p518 ).
For each element, user agents must establish a default behavior, either through defaults or through preferences
expressed by the user. There are three possible default behaviors for each element:
true-by-default
The element will be checked for spelling and grammar if its contents are editable.
false-by-default
The element will never be checked for spelling and grammar.
520
inherit-by-default
The element's default behavior is the same as its parent element's. Elements that have no parent element
cannot have this as their default behavior.
The spellcheck attribute is an enumerated attribute p34 whose keywords are the empty string, true and false.
The empty string and the true keyword map to the true state. The false keyword maps to the false state. In
addition, there is a third state, the default state, which is the missing value default (and the invalid value default).
The true state indicates that the element is to have its spelling and grammar checked. The default state indicates
that the element is to act according to a default behavior, possibly based on the parent element's own
spellcheck p521 state. The false state indicates that the element is not to be checked.
This box is non-normative. Implementation requirements are given below this box.
element . spellcheck
p521
[ = value ]
Returns "true", "false", or "default", based on the state of the spellcheck p521 attribute.
Can be set, to change that state.
Throws a SYNTAX_ERR p70 exception if the new value isn't one of those strings.
The spellcheck IDL attribute, on getting, must return the string "true" if the content attribute is set to the true
state, false" if the content attribute is set to the false state, and "default" otherwise. On setting, if the new
value is an ASCII case-insensitive p33 match for the string "default" then the content attribute must be removed, if
the new value is an ASCII case-insensitive p33 match for the string "true" then the content attribute must be set to
the string "true", if the new value is an ASCII case-insensitive p33 match for the string "false" then the content
attribute must be set to the string "false", and otherwise the attribute setter must raise a SYNTAX_ERR p70
exception.
Note: The spellcheck p521 IDL attribute is not affected by user preferences that override the
spellcheck p521 content attribute, and therefore might not reflect the actual spellchecking
state.
On setting, if the new value is true, then the element's spellcheck p521 content attribute must be set to the literal
string "true", otherwise it must be set to the literal string "false".
User agents must only consider the following pieces of text as checkable for the purposes of this feature:
•
The value of input p303 elements to which the readonly p325 attribute applies, whose type p304 attributes
are not in the Password p310 state, and that are not immutable p306 (i.e. that do not have the readonly p325
attribute specified and that are not disabled p354 ).
•
The value of textarea p341 elements that do not have a readonly p342 attribute and that are not
disabled p354 .
•
Text in text nodes p27 that are children of editable p518 elements.
•
Text in attributes of editable p518 elements.
For text that is part of a text node p27 , the element with which the text is associated is the element that is the
immediate parent of the first character of the word, sentence, or other piece of text. For text in attributes, it is the
attribute's element. For the values of input p303 and textarea p341 elements, it is the element itself.
To determine if a word, sentence, or other piece of text in an applicable element (as defined above) is to have
spelling- and/or grammar-checking enabled, the UA must use the following algorithm:
1.
If the user has disabled the checking for this text, then the checking is disabled.
2.
Otherwise, if the user has forced the checking for this text to always be enabled, then the checking is
enabled.
3.
Otherwise, if the element with which the text is associated has a spellcheck p521 content attribute, then:
if that attribute is in the true state, then checking is enabled; otherwise, if that attribute is in the false
state, then checking is disabled.
4.
Otherwise, if there is an ancestor element with a spellcheck p521 content attribute that is not in the
default state, then: if the nearest such ancestor's spellcheck p521 content attribute is in the true state,
then checking is enabled; otherwise, checking is disabled.
5.
Otherwise, if the element's default behavior p520 is true-by-default p520 , then checking is enabled.
521
6.
Otherwise, if the element's default behavior p520 is false-by-default p520 , then checking is disabled.
7.
Otherwise, if the element's parent element has its checking enabled, then checking is enabled.
8.
Otherwise, checking is disabled.
If the checking is enabled for a word/sentence/text, the user agent should indicate spelling and/or grammar errors
in that text. User agents should take into account the other semantics given in the document when suggesting
spelling and grammar corrections. User agents may use the language of the element to determine what spelling
and grammar rules to use, or may use the user's preferred language settings. UAs should use input p303 element
attributes such as pattern p328 to ensure that the resulting value is valid, where possible.
If checking is disabled, the user agent should not indicate spelling or grammar errors for that text.
The element with ID "a" in the following example would be the one used to determine if the word "Hello" is
checked for spelling errors. In this example, it would not be.
Hell o!
The element with ID "b" in the following example would have checking enabled (the leading space character
in the attribute's value on the input p303 element causes the attribute to be ignored, so the ancestor's value
is used instead, regardless of the default).
Name:
Note: This specification does not define the user interface for spelling and grammar checkers.
A user agent could offer on-demand checking, could perform continuous checking while the
checking is enabled, or could use other interfaces.
8.9 Drag and drop
This section defines an event-based drag-and-drop mechanism.
This specification does not define exactly what a drag-and-drop operation actually is.
On a visual medium with a pointing device, a drag operation could be the default action of a mousedown event that
is followed by a series of mousemove events, and the drop could be triggered by the mouse being released.
On media without a pointing device, the user would probably have to explicitly indicate his intention to perform a
drag-and-drop operation, stating what he wishes to drag and what he wishes to drop, respectively.
However it is implemented, drag-and-drop operations must have a starting point (e.g. where the mouse was
clicked, or the start of the selection p514 or element that was selected for the drag), may have any number of
intermediate steps (elements that the mouse moves over during a drag, or elements that the user picks as
possible drop points as he cycles through possibilities), and must either have an end point (the element above
which the mouse button was released, or the element that was finally selected), or be canceled. The end point
must be the last element selected as a possible drop point before the drop occurs (so if the operation is not
canceled, there must be at least one element in the middle step).
8.9.1 Introduction
This section is non-normative.
To make an element draggable is simple: give the element a draggable p531 attribute, and set an event listener for
dragstart p526 that stores the data being dragged.
The event handler typically needs to check that it's not a text selection that is being dragged, and then needs to
store data into the DataTransfer p524 object and set the allowed effects (copy, move, link, or some combination).
For example:
What fruits do you like?
Apples
Oranges
Pears
To accept a drop, the drop target has to listen to at least three events. First, the dragenter p526 event, which is
used to determine whether or not the drop target is to accept the drop. If the drop is to be accepted, then this
event has to be canceled. Second, the dragover p526 event, which is used to determine what feedback is to be
shown to the user. If the event is canceled, then the feedback (typically the cursor) is updated based on the
dropEffect p525 attribute's value, as set by the event handler; otherwise, the default behavior (typically to do
nothing) is used instead. Finally, the drop p526 event, which allows the actual drop to be performed. This event also
needs to be canceled, so that the dropEffect p525 attribute's value can be used by the source (otherwise it's reset).
For example:
Drop your favorite fruits below:
To remove the original element (the one that was dragged) from the display, the dragend p526 event can be used.
For our example here, that means updating the original markup to handle that event:
What fruits do you like?
...as before...
8.9.2 The DragEvent p524 and DataTransfer p524 interfaces
The drag-and-drop processing model involves several events. They all use the DragEvent p524 interface.
interface DragEvent : MouseEvent {
readonly attribute DataTransfer dataTransfer;
void initDragEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in any dummyArg, in long detailArg, in long screenXArg, in long
screenYArg, in long clientXArg, in long clientYArg, in boolean ctrlKeyArg, in boolean
altKeyArg, in boolean shiftKeyArg, in boolean metaKeyArg, in unsigned short buttonArg,
in EventTarget relatedTargetArg, in DataTransfer dataTransferArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . dataTransfer
p524
Returns the DataTransfer p524 object for the event.
The initDragEvent() method must initialize the event in a manner analogous to the similarly-named method in
the DOM Events interfaces, except that the dummyArg argument must be ignored. [DOMEVENTS] p701
The dataTransfer attribute of the DragEvent p524 interface represents the context information for the event.
interface DataTransfer {
attribute DOMString dropEffect;
attribute DOMString effectAllowed;
readonly attribute DOMStringList types;
void clearData(in optional DOMString format);
void setData(in DOMString format, in DOMString data);
DOMString getData(in DOMString format);
readonly attribute FileList files;
void setDragImage(in Element image, in long x, in long y);
void addElement(in Element element);
};
DataTransfer p524 objects can hold pieces of data, each associated with a unique format. Formats are generally
given by MIME types p26 , with some values special-cased for legacy reasons. However, the API does not enforce
this; non-MIME-type values can be added as well. All formats are identified by strings that are converted to ASCII
lowercase p33 by the API.
This box is non-normative. Implementation requirements are given below this box.
dataTransfer . dropEffect p525 [ = value ]
Returns the kind of operation that is currently selected. If the kind of operation isn't one of those that
is allowed by the effectAllowed p525 attribute, then the operation will fail.
Can be set, to change the selected operation.
The possible values are none, copy, link, and move.
dataTransfer . effectAllowed p525 [ = value ]
Returns the kinds of operations that are to be allowed.
Can be set, to change the allowed operations.
The possible values are none, copy, copyLink, copyMove, link, linkMove, move, all, and
uninitialized,
524
dataTransfer . types p525
Returns a DOMStringList listing the formats that were set in the dragstart p526 event. In addition, if
any files are being dragged, then one of the types will be the string "Files".
dataTransfer . clearData p525 ( [ format ] )
Removes the data of the specified formats. Removes all data if the argument is omitted.
dataTransfer . setData p525 (format, data)
Adds the specified data.
data = dataTransfer . getData p525 (format)
Returns the specified data. If there is no such data, returns the empty string.
dataTransfer . files p526
Returns a FileList of the files being dragged, if any.
dataTransfer . setDragImage p526 (element, x, y)
Uses the given element to update the drag feedback, replacing any previously specified feedback.
dataTransfer . addElement p526 (element)
Adds the given element to the list of elements used to render the drag feedback.
When a DataTransfer p524 object is created, it must be initialized as follows:
•
The DataTransfer p524 object must initially contain no data, no elements, and have no associated image.
•
The DataTransfer p524 object's effectAllowed p525 attribute must be set to "uninitialized".
•
The dropEffect p525 attribute must be set to "none".
The dropEffect attribute controls the drag-and-drop feedback that the user is given during a drag-and-drop
operation.
The attribute must ignore any attempts to set it to a value other than none, copy, link, and move. On getting, the
attribute must return the last of those four values that it was set to.
The effectAllowed attribute is used in the drag-and-drop processing model to initialize the dropEffect p525
attribute during the dragenter p526 and dragover p526 events.
The attribute must ignore any attempts to set it to a value other than none, copy, copyLink, copyMove, link,
linkMove, move, all, and uninitialized. On getting, the attribute must return the last of those values that it was
set to.
The types attribute must return a live p27 DOMStringList that contains the list of formats that were added to the
DataTransfer p524 object in the corresponding dragstart p526 event. The same object must be returned each time.
If any files were included in the drag, then the DOMStringList object must in addition include the string "Files".
(This value can be distinguished from the other values because it is not lowercase.)
The clearData() method, when called with no arguments, must clear the DataTransfer p524 object of all data (for
all formats).
Note: The clearData() p525 method does not affect whether any files were included in the drag,
so the types p525 attribute's list might still not be empty after calling clearData() p525 (it would
still contain the "Files" string if any files were included in the drag).
When called with an argument, the clearData(format) p525 method must clear the DataTransfer p524 object of any
data associated with the given format, converted to ASCII lowercase p33 . If format (after conversion to lowercase) is
the value "text", then it must be treated as "text/plain". If the format (after conversion to lowercase) is "url",
then it must be treated as "text/uri-list".
The setData(format, data) method must add data to the data stored in the DataTransfer p524 object, labeled as
being of the type format, converted to ASCII lowercase p33 . This must replace any previous data that had been set
for that format. If format (after conversion to lowercase) is the value "text", then it must be treated as "text/
plain". If the format (after conversion to lowercase) is "url", then it must be treated as "text/uri-list".
The getData(format) method must return the data that is associated with the type format converted to ASCII
lowercase p33 , if any, and must return the empty string otherwise. If format (after conversion to lowercase) is the
value "text", then it must be treated as "text/plain". If the format (after conversion to lowercase) is "url", then
525
the data associated with the "text/uri-list" format must be parsed as appropriate for text/uri-list data, and
the first URL from the list must be returned. If there is no data with that format, or if there is but it has no URLs,
then the method must return the empty string. [RFC2483] p703
The files attribute must return the FileList object that contains the files that are stored in the
DataTransfer p524 object. There is one such object per DataTransfer p524 object.
Note: This version of the API does not expose the types of the files during the drag.
The setDragImage(element, x, y) method sets which element to use to generate the drag feedback p528 . The
element argument can be any Element p31 ; if it is an img p186 element, then the user agent should use the element's
image (at its intrinsic size) to generate the feedback, otherwise the user agent should base the feedback on the
given element (but the exact mechanism for doing so is not specified).
The addElement(element) method is an alternative way of specifying how the user agent is to render the drag
feedback p528 . It adds an element to the DataTransfer p524 object.
Note: The difference between setDragImage() p526 and addElement() p526 is that the latter
automatically generates the image based on the current rendering of the elements added,
whereas the former uses the exact specified image.
8.9.3 Events fired during a drag-and-drop action
The following events are involved in the drag-and-drop model.
Whenever the processing model described below causes one of these events to be fired, the event fired must use
the DragEvent p524 interface defined above, must have the bubbling and cancelable behaviors given in the table
below, and must have the context information set up as described after the table, with the detail attribute set to
zero, the mouse and key attributes set according to the state of the input devices as they would be for user
interaction events, and the relatedTarget attribute set to null.
If there is no relevant pointing device, the object must have its screenX, screenY, clientX, clientY, and button
attributes set to 0.
Event
Name
Target
Bubbles? Cancelable?
dataTransfer
effectAllowed p525 dropEffect p525
Default
Action
dragstart Source
node p527
✓
Bubbles
✓ Cancelable Contains source node p527 unless uninitialized
a selection is being dragged, in
which case it is empty;
files p526 returns any files
included in the drag operation
none
Initiate the
drag-and-drop
operation
drag
✓
Bubbles
✓ Cancelable Empty
Same as last
event p527
none
Continue the
drag-and-drop
operation
dragenter Immediate ✓
user
Bubbles
selection p528
or the body
element p76
✓ Cancelable Empty
Same as last
event p527
Based on
Reject
effectAllowed immediate
user
value p527
selection p528
as potential
target
element p528
dragleave Previous
target
element p528
✓
Bubbles
—
Empty
Same as last
event p527
none
dragover
Current
target
element p528
✓
Bubbles
✓ Cancelable Empty
Same as last
event p527
Based on
Reset the
effectAllowed current drag
value p527
operation p528
to "none"
drop
Current
target
element p528
✓
Bubbles
✓ Cancelable getData() p525 returns data set
in dragstart event; files p526
returns any files included in the
drag operation
Same as last
event p527
Current drag
operation p528
Varies
dragend
Source
node p527
✓
Bubbles
—
Same as last
event p527
Current drag
operation p528
Varies
Source
node p527
Empty
None
Note: "Empty" in the table above means that the getData() p525 and files p526 attributes act as if
there is no data being dragged.
The dataTransfer p524 object's contents are empty (the getData() p525 and files p526 attributes act as if there is no
data being dragged) except for dragstart p526 events and drop p526 events, for which the contents are set as
described in the processing model, below.
526
The effectAllowed p525 attribute must be set to "uninitialized" for dragstart p526 events, and to whatever value
the field had after the last drag-and-drop event was fired for all other events (only counting events fired by the
user agent for the purposes of the drag-and-drop model described below).
The dropEffect p525 attribute must be set to "none" for dragstart p526 , drag p526 , and dragleave p526 events (except
when stated otherwise in the algorithms given in the sections below), to the value corresponding to the current
drag operation p528 for drop p526 and dragend p526 events, and to a value based on the effectAllowed p525 attribute's
value and to the drag-and-drop source, as given by the following table, for the remaining events (dragenter p526
and dragover p526 ):
effectAllowed p525
dropEffect p525
none
none
copy, copyLink, copyMove, all
copy
link, linkMove
link
move
move
uninitialized when what is being dragged is a selection from a text field
move
uninitialized when what is being dragged is a selection
copy
uninitialized when what is being dragged is an a p160 element with an href attribute link
Any other case
copy
8.9.4 Drag-and-drop processing model
When the user attempts to begin a drag operation, the user agent must first determine what is being dragged. If
the drag operation was invoked on a selection, then it is the selection that is being dragged. Otherwise, it is the
first element, going up the ancestor chain, starting at the node that the user tried to drag, that has the IDL
attribute draggable p531 set to true. If there is no such element, then nothing is being dragged, the drag-and-drop
operation is never started, and the user agent must not continue with this algorithm.
Note: img p186 elements and a p160 elements with an href p383 attribute have their draggable p531
attribute set to true by default.
If the user agent determines that something can be dragged, a dragstart p526 event must then be fired at the
source node p527 .
The source node depends on the kind of drag and how it was initiated. If it is a selection that is being dragged,
then the source node p527 is the text node that the user started the drag on (typically the text node that the user
originally clicked). If the user did not specify a particular node, for example if the user just told the user agent to
begin a drag of "the selection", then the source node p527 is the first text node containing a part of the selection. If
it is not a selection that is being dragged, then the source node p527 is the element that is being dragged.
Multiple events are fired on the source node p527 during the course of the drag-and-drop operation.
The list of dragged nodes also depends on the kind of drag. If it is a selection that is being dragged, then the
list of dragged nodes p527 contains, in tree order p27 , every node that is partially or completely included in the
selection (including all their ancestors). Otherwise, the list of dragged nodes p527 contains only the source node p527 .
If it is a selection that is being dragged, the dataTransfer p524 member of the event must be created with no
nodes. Otherwise, it must be created containing just the source node p527 . Script can use the addElement() p526
method to add further elements to the list of what is being dragged. (This list is only used for rendering the drag
feedback.)
The dataTransfer p524 member of the event also has data added to it, as follows:
•
If it is a selection that is being dragged, then the user agent must add the text of the selection to the
dataTransfer p524 member, associated with the text/plain format.
•
If files are being dragged, then the user agent must add the files to the dataTransfer p524 member's
files p526 attribute's FileList object. (Dragging files can only happen from outside a browsing
context p439 , for example from a file system manager application, and thus the dragstart p526 event is
actually implied in this case.)
•
The user agent must take the list of dragged nodes p527 and extract the microdata from those nodes into
a JSON form p431 , and then must add the resulting string to the dataTransfer p524 member, associated
with the application/microdata+json format.
•
The user agent must run the following steps:
1.
Let urls be an empty list of absolute URLs p52 .
527
2.
For each node in nodes:
If the node is an a p160 element with an href p383
Add to urls the result of resolving p51 the element's href p383 content attribute relative to
the element.
If the node is an img p186 element with an src p186
Add to urls the result of resolving p51 the element's src p186 content attribute relative to
the element.
3.
If urls is still empty, abort these steps.
4.
Let url string be the result of concatenating the strings in urls, in the order they were added,
separated by a U+000D CARRIAGE RETURN U+000A LINE FEED character pair (CRLF).
5.
Add url string to the dataTransfer p524 member, associated with the text/uri-list format.
If the event is canceled, then the drag-and-drop operation must not occur; the user agent must not continue with
this algorithm.
If it is not canceled, then the drag-and-drop operation must be initiated.
Note: Since events with no event listeners registered are, almost by definition, never
canceled, drag-and-drop is always available to the user if the author does not specifically
prevent it.
The drag-and-drop feedback must be generated from the first of the following sources that is available:
1.
The element specified in the last call to the setDragImage() p526 method of the dataTransfer p524 object
of the dragstart p526 event, if the method was called. In visual media, if this is used, the x and y
arguments that were passed to that method should be used as hints for where to put the cursor relative
to the resulting image. The values are expressed as distances in CSS pixels from the left side and from
the top side of the image respectively. [CSS] p700
2.
The elements that were added to the dataTransfer p524 object, both before the event was fired, and
during the handling of the event using the addElement() p526 method, if any such elements were indeed
added.
3.
The selection that the user is dragging.
The user agent must take a note of the data that was placed p525 in the dataTransfer p524 object. This data will be
made available again when the drop p526 event is fired.
From this point until the end of the drag-and-drop operation, device input events (e.g. mouse and keyboard
events) must be suppressed. In addition, the user agent must track all DOM changes made during the drag-anddrop operation, and add them to its undo history p532 as one atomic operation once the drag-and-drop operation
has ended.
During the drag operation, the element directly indicated by the user as the drop target is called the immediate
user selection. (Only elements can be selected by the user; other nodes must not be made available as drop
targets.) However, the immediate user selection p528 is not necessarily the current target element, which is the
element currently selected for the drop part of the drag-and-drop operation. The immediate user selection p528
changes as the user selects different elements (either by pointing at them with a pointing device, or by selecting
them in some other way). The current target element p528 changes when the immediate user selection p528 changes,
based on the results of event listeners in the document, as described below.
Both the current target element p528 and the immediate user selection p528 can be null, which means no target
element is selected. They can also both be elements in other (DOM-based) documents, or other (non-Web)
programs altogether. (For example, a user could drag text to a word-processor.) The current target element p528 is
initially null.
In addition, there is also a current drag operation, which can take on the values "none", "copy", "link", and
"move". Initially, it has the value "none". It is updated by the user agent as described in the steps below.
User agents must, as soon as the drag operation is initiated and every 350ms (±200ms) thereafter for as long as
the drag operation is ongoing, queue a task p490 to perform the following steps in sequence:
528
1.
If the user agent is still performing the previous iteration of the sequence (if any) when the next iteration
becomes due, the user agent must not execute the overdue iteration, effectively "skipping missed
frames" of the drag-and-drop operation.
2.
The user agent must fire a drag p526 event at the source node p527 . If this event is canceled, the user agent
must set the current drag operation p528 to none (no drag operation).
3.
Next, if the drag p526 event was not canceled and the user has not ended the drag-and-drop operation,
the user agent must check the state of the drag-and-drop operation, as follows:
1.
First, if the user is indicating a different immediate user selection p528 than during the last
iteration (or if this is the first iteration), and if this immediate user selection p528 is not the same
as the current target element p528 , then the current target element p528 must be updated, as
follows:
p528
is null, or is in a non-DOM document or
↪ If the new immediate user selection
application
The user agent must set the current target element p528 to the same value.
↪ Otherwise
The user agent must fire a dragenter p526 event at the immediate user selection p528 .
If the event is canceled, then the current target element p528 must be set to the
immediate user selection p528 .
Otherwise, the user agent must act as follows:
p528
is a text field (e.g. textarea p341 , or an
↪ If the current target element
input p303 element whose type p304 attribute is in the Text p307 state) or an
editable p518 element
The current target element p528 must be set to the immediate user
selection p528 anyway.
p528
is the body element p76
↪ If the current target element
The current target element p528 is left unchanged.
↪ Otherwise
The user agent must fire a dragenter p526 event at the body element p76 , and
the current target element p528 must be set to the body element p76 ,
regardless of whether that event was canceled or not. (If the body
element p76 is null, then the current target element p528 would be set to null
too in this case, it wouldn't be set to the Document p31 object.)
2.
If the previous step caused the current target element p528 to change, and if the previous target
element was not null or a part of a non-DOM document, the user agent must fire a
dragleave p526 event at the previous target element.
3.
If the current target element p528 is a DOM element, the user agent must fire a dragover p526
event at this current target element p528 .
If the dragover p526 event is not canceled, the user agent must act as follows:
p528
is a text field (e.g. textarea p341 , or an input p303
↪ If the current target element
element whose type p304 attribute is in the Text p307 state) or an editable p518
element
The user agent must set the current drag operation p528 to either "copy" or "move", as
appropriate given the platform conventions.
↪ Otherwise
The user agent must reset the current drag operation p528 to "none".
Otherwise (if the dragover p526 event is canceled), the current drag operation p528 must be set
based on the values the effectAllowed p525 and dropEffect p525 attributes of the
dataTransfer p524 object had after the event was handled, as per the following table:
effectAllowed p525
dropEffect p525 Drag operation
uninitialized, copy, copyLink, copyMove, or all copy
"copy"
uninitialized, link, copyLink, linkMove, or all link
"link"
uninitialized, move, copyMove, linkMove, or all move
"move"
Any other case
"none"
Then, regardless of whether the dragover p526 event was canceled or not, the drag feedback
(e.g. the mouse cursor) must be updated to match the current drag operation p528 , as follows:
Drag operation
Feedback
"copy"
Data will be copied if dropped here.
"link"
Data will be linked if dropped here.
"move"
Data will be moved if dropped here.
529
Drag operation
"none"
4.
4.
Feedback
No operation allowed, dropping here will cancel the drag-and-drop operation.
Otherwise, if the current target element p528 is not a DOM element, the user agent must use
platform-specific mechanisms to determine what drag operation is being performed (none,
copy, link, or move). This sets the current drag operation.
Otherwise, if the user ended the drag-and-drop operation (e.g. by releasing the mouse button in a
mouse-driven drag-and-drop interface), or if the drag p526 event was canceled, then this will be the last
iteration. The user agent must execute the following steps, then stop looping.
1.
If the current drag operation p528 is none (no drag operation), or, if the user ended the dragand-drop operation by canceling it (e.g. by hitting the Escape key), or if the current target
element p528 is null, then the drag operation failed. If the current target element p528 is a DOM
element, the user agent must fire a dragleave p526 event at it; otherwise, if it is not null, it
must use platform-specific conventions for drag cancellation.
2.
Otherwise, the drag operation was as success. If the current target element p528 is a DOM
element, the user agent must fire a drop p526 event at it; otherwise, it must use platformspecific conventions for indicating a drop.
When the target is a DOM element, the dropEffect p525 attribute of the event's
dataTransfer p524 object must be given the value representing the current drag operation p528
(copy, link, or move), and the object must be set up so that the getData() p525 method will
return the data that was added during the dragstart p526 event, and the files p526 attribute will
return a FileList object with any files that were dragged.
If the event is canceled, the current drag operation p528 must be set to the value of the
dropEffect p525 attribute of the event's dataTransfer p524 object as it stood after the event was
handled.
Otherwise, the event is not canceled, and the user agent must perform the event's default
action, which depends on the exact target as follows:
p528
is a text field (e.g. textarea p341 , or an input p303
↪ If the current target element
p304
element whose type
attribute is in the Text p307 state) or an editable p518
element
The user agent must insert the data associated with the text/plain format, if any,
into the text field or editable p518 element in a manner consistent with platformspecific conventions (e.g. inserting it at the current mouse cursor position, or
inserting it at the end of the field).
↪ Otherwise
Reset the current drag operation p528 to "none".
3.
Finally, the user agent must fire a dragend p526 event at the source node p527 , with the
dropEffect p525 attribute of the event's dataTransfer p524 object being set to the value
corresponding to the current drag operation p528 .
Note: The current drag operation p528 can change during the processing of the
drop p526 event, if one was fired.
The event is not cancelable. After the event has been handled, the user agent must act as
follows:
p528
is a text field (e.g. textarea p341 , or an input p303
↪ If the current target element
p304
element whose type
attribute is in the Text p307 state), and a drop p526 event
was fired in the previous step, and the current drag operation p528 is "move", and
the source of the drag-and-drop operation is a selection in the DOM
The user agent should delete the range representing the dragged selection from the
DOM.
p528
is a text field (e.g. textarea p341 , or an input p303
↪ If the current target element
element whose type p304 attribute is in the Text p307 state), and a drop p526 event
was fired in the previous step, and the current drag operation p528 is "move", and
the source of the drag-and-drop operation is a selection in a text field
The user agent should delete the dragged selection from the relevant text field.
↪ Otherwise
The event has no default action.
530
8.9.4.1 When the drag-and-drop operation starts or ends in another document
The model described above is independent of which Document p31 object the nodes involved are from; the events
must be fired as described above and the rest of the processing model must be followed as described above,
irrespective of how many documents are involved in the operation.
8.9.4.2 When the drag-and-drop operation starts or ends in another application
If the drag is initiated in another application, the source node p527 is not a DOM node, and the user agent must use
platform-specific conventions instead when the requirements above involve the source node. User agents in this
situation must act as if the dragged data had been added to the DataTransfer p524 object when the drag started,
even though no dragstart p526 event was actually fired; user agents must similarly use platform-specific
conventions when deciding on what drag feedback to use.
All the format strings must be converted to ASCII lowercase p33 . If the platform conventions do not use MIME
types p26 to label the dragged data, the user agent must map the types to MIME types first.
If a drag is started in a document but ends in another application, then the user agent must instead replace the
parts of the processing model relating to handling the target according to platform-specific conventions.
In any case, scripts running in the context of the document must not be able to distinguish the case of a drag-anddrop operation being started or ended in another application from the case of a drag-and-drop operation being
started or ended in another document from another domain.
8.9.5 The draggable attribute
All HTML elements p26 may have the draggable p531 content attribute set. The draggable p531 attribute is an
enumerated attribute p34 . It has three states. The first state is true and it has the keyword true. The second state
is false and it has the keyword false. The third state is auto; it has no keywords but it is the missing value default.
The true state means the element is draggable; the false state means that it is not. The auto state uses the
default behavior of the user agent.
This box is non-normative. Implementation requirements are given below this box.
element . draggable
p531
[ = value ]
Returns true if the element is draggable; otherwise, returns false.
Can be set, to override the default and set the draggable p531 content attribute.
The draggable IDL attribute, whose value depends on the content attribute's in the way described below, controls
whether or not the element is draggable. Generally, only text selections are draggable, but elements whose
draggable p531 IDL attribute is true become draggable as well.
If an element's draggable p531 content attribute has the state true, the draggable p531 IDL attribute must return
true.
Otherwise, if the element's draggable p531 content attribute has the state false, the draggable p531 IDL attribute
must return false.
Otherwise, the element's draggable p531 content attribute has the state auto. If the element is an img p186 element,
or, if the element is an a p160 element with an href p383 content attribute, the draggable p531 IDL attribute must
return true.
Otherwise, the draggable p531 DOM must return false.
If the draggable p531 IDL attribute is set to the value false, the draggable p531 content attribute must be set to the
literal value false. If the draggable p531 IDL attribute is set to the value true, the draggable p531 content attribute
must be set to the literal value true.
8.9.6 Security risks in the drag-and-drop model
User agents must not make the data added to the DataTransfer p524 object during the dragstart p526 event
available to scripts until the drop p526 event, because otherwise, if a user were to drag sensitive information from
one document to a second document, crossing a hostile third document in the process, the hostile document could
intercept the data.
531
For the same reason, user agents must consider a drop to be successful only if the user specifically ended the
drag operation — if any scripts end the drag operation, it must be considered unsuccessful (canceled) and the
drop p526 event must not be fired.
User agents should take care to not start drag-and-drop operations in response to script actions. For example, in a
mouse-and-window environment, if a script moves a window while the user has his mouse button depressed, the
UA would not consider that to start a drag. This is important because otherwise UAs could cause data to be
dragged from sensitive sources and dropped into hostile documents without the user's consent.
8.10 Undo history
8.10.1 Definitions
The user agent must associate an undo transaction history with each HTMLDocument p71 object.
The undo transaction history p532 is a list of entries. The entries are of two types: DOM changes p532 and undo
objects p532 .
Each DOM changes entry in the undo transaction history p532 consists of batches of one or more of the following:
•
Changes to the content attributes of an Element p31 node.
•
Changes to the DOM hierarchy of nodes that are descendants of the HTMLDocument p71 object
(parentNode p31 , childNodes p31 ).
•
Changes to internal state, such as a form control's value p354 or dirty checkedness flag p306 .
Undo object entries consist of objects representing state that scripts running in the document are managing. For
example, a Web mail application could use an undo object p532 to keep track of the fact that a user has moved an email to a particular folder, so that the user can undo the action and have the e-mail return to its former location.
Broadly speaking, DOM changes p532 entries are handled by the UA in response to user edits of form controls and
editing hosts p518 on the page, and undo object p532 entries are handled by script in response to higher-level user
actions (such as interactions with server-side state, or in the implementation of a drawing tool).
8.10.2 The UndoManager p532 interface
To manage undo object p532 entries in the undo transaction history p532 , the UndoManager p532 interface can be used:
interface UndoManager {
readonly attribute unsigned long length;
getter any item(in unsigned long index);
readonly attribute unsigned long position;
unsigned long add(in any data, in DOMString title);
void remove(in unsigned long index);
void clearUndo();
void clearRedo();
};
This box is non-normative. Implementation requirements are given below this box.
window . undoManager
p533
Returns the UndoManager p532 object.
undoManager . length p533
Returns the number of entries in the undo history.
data = undoManager . item p533 (index)
undoManager[index]
Returns the entry with index index in the undo history.
Returns null if index is out of range.
undoManager . position p533
Returns the number of the current entry in the undo history. (Entries at and past this point are redo
entries.)
532
undoManager . add p533 (data, title)
Adds the specified entry to the undo history.
undoManager . remove p533 (index)
Removes the specified entry to the undo history.
Throws an INDEX_SIZE_ERR p70 exception if the given index is out of range.
undoManager . clearUndo p533 ()
Removes all entries before the current position in the undo history.
undoManager . clearRedo p533 ()
Removes all entries at and after the current position in the undo history.
The undoManager attribute of the Window p443 interface must return the object implementing the UndoManager p532
interface for that Window p443 object's associated HTMLDocument p71 object.
UndoManager p532 objects represent their document's undo transaction history p532 . Only undo object p532 entries are
visible with this API, but this does not mean that DOM changes p532 entries are absent from the undo transaction
history p532 .
The length attribute must return the number of undo object p532 entries in the undo transaction history p532 . This is
the length p533 .
The object's indices of the supported indexed properties are the numbers in the range zero to length p533 -1, unless
the length p533 is zero, in which case there are no supported indexed properties.
The item(n) method must return the nth undo object p532 entry in the undo transaction history p532 , if there is one,
or null otherwise.
The undo transaction history p532 has a current position. This is the position between two entries in the undo
transaction history p532 's list where the previous entry represents what needs to happen if the user invokes the
"undo" command (the "undo" side, lower numbers), and the next entry represents what needs to happen if the
user invokes the "redo" command (the "redo" side, higher numbers).
The position attribute must return the index of the undo object p532 entry nearest to the undo position p533 , on the
"redo" side. If there are no undo object p532 entries on the "redo" side, then the attribute must return the same as
the length p533 attribute. If there are no undo object p532 entries on the "undo" side of the undo position p533 , the
position p533 attribute returns zero.
Note: Since the undo transaction history p532 contains both undo object p532 entries and DOM
changes p532 entries, but the position p533 attribute only returns indices relative to undo
object p532 entries, it is possible for several "undo" or "redo" actions to be performed without
the value of the position p533 attribute changing.
The add(data, title) method's behavior depends on the current state. Normally, it must insert the data object
passed as an argument into the undo transaction history p532 immediately before the undo position p533 , optionally
remembering the given title to use in the UI. If the method is called during an undo operation p534 , however, the
object must instead be added immediately after the undo position p533 .
If the method is called and there is neither an undo operation in progress p534 nor a redo operation in progress p534
then any entries in the undo transaction history p532 after the undo position p533 must be removed (as if
clearRedo() p533 had been called).
The remove(index) method must remove the undo object p532 entry with the specified index. If the index is less
than zero or greater than or equal to length p533 then the method must raise an INDEX_SIZE_ERR p70 exception.
DOM changes p532 entries are unaffected by this method.
The clearUndo() method must remove all entries in the undo transaction history p532 before the undo position p533 ,
be they DOM changes p532 entries or undo object p532 entries.
The clearRedo() method must remove all entries in the undo transaction history p532 after the undo position p533 ,
be they DOM changes p532 entries or undo object p532 entries.
533
8.10.3 Undo: moving back in the undo transaction history
When the user invokes an undo operation, or when the execCommand() p535 method is called with the undo p538
command, the user agent must perform an undo operation.
If the undo position p533 is at the start of the undo transaction history p532 , then the user agent must do nothing.
If the entry immediately before the undo position p533 is a DOM changes p532 entry, then the user agent must
remove that DOM changes p532 entry, reverse the DOM changes that were listed in that entry, and, if the changes
were reversed with no problems, add a new DOM changes p532 entry (consisting of the opposite of those DOM
changes) to the undo transaction history p532 on the other side of the undo position p533 .
If the DOM changes cannot be undone (e.g. because the DOM state is no longer consistent with the changes
represented in the entry), then the user agent must simply remove the DOM changes p532 entry, without doing
anything else.
If the entry immediately before the undo position p533 is an undo object p532 entry, then the user agent must first
remove that undo object p532 entry from the undo transaction history p532 , and then must fire an undo p534 event at
the Window p443 object, using the undo object p532 entry's associated undo object as the event's data.
Any calls to add() p533 while the event is being handled will be used to populate the redo history, and will then be
used if the user invokes the "redo" command to undo his undo.
8.10.4 Redo: moving forward in the undo transaction history
When the user invokes a redo operation, or when the execCommand() p535 method is called with the redo p538
command, the user agent must perform a redo operation.
This is mostly the opposite of an undo operation p534 , but the full definition is included here for completeness.
If the undo position p533 is at the end of the undo transaction history p532 , then the user agent must do nothing.
If the entry immediately after the undo position p533 is a DOM changes p532 entry, then the user agent must remove
that DOM changes p532 entry, reverse the DOM changes that were listed in that entry, and, if the changes were
reversed with no problems, add a new DOM changes p532 entry (consisting of the opposite of those DOM changes)
to the undo transaction history p532 on the other side of the undo position p533 .
If the DOM changes cannot be redone (e.g. because the DOM state is no longer consistent with the changes
represented in the entry), then the user agent must simply remove the DOM changes p532 entry, without doing
anything else.
If the entry immediately after the undo position p533 is an undo object p532 entry, then the user agent must first
remove that undo object p532 entry from the undo transaction history p532 , and then must fire a redo p534 event at the
Window p443 object, using the undo object p532 entry's associated undo object as the event's data.
8.10.5 The UndoManagerEvent p534 interface and the undo p534 and redo p534 events
interface UndoManagerEvent : Event {
readonly attribute any data;
void initUndoManagerEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in any dataArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . data p534
Returns the data that was passed to the add() p533 method.
The initUndoManagerEvent() method must initialize the event in a manner analogous to the similarly-named
method in the DOM Events interfaces. [DOMEVENTS] p701
The data attribute represents the undo object p532 for the event.
The undo and redo events do not bubble, cannot be canceled, and have no default action. When the user agent
fires one of these events it must use the UndoManagerEvent p534 interface, with the data p534 field containing the
relevant undo object p532 .
534
8.10.6 Implementation notes
How user agents present the above conceptual model to the user is not defined. The undo interface could be a
filtered view of the undo transaction history p532 , it could manipulate the undo transaction history p532 in ways not
described above, and so forth. For example, it is possible to design a UA that appears to have separate undo
transaction histories p532 for each form control; similarly, it is possible to design systems where the user has access
to more undo information than is present in the official (as described above) undo transaction history p532 (such as
providing a tree-based approach to document state). Such UI models should be based upon the single undo
transaction history p532 described in this section, however, such that to a script there is no detectable difference.
8.11 Editing APIs
This box is non-normative. Implementation requirements are given below this box.
document . execCommand p535 (commandId [, showUI [, value ] ] )
Runs the action specified by the first argument, as described in the list below. The second and third
arguments sometimes affect the action. (If they don't they are ignored.)
document . queryCommandEnabled p535 (commandId)
Returns whether the given command is enabled, as described in the list below.
document . queryCommandIndeterm p535 (commandId)
Returns whether the given command is indeterminate, as described in the list below.
document . queryCommandState p535 (commandId)
Returns the state of the command, as described in the list below.
document . queryCommandSupported p535 (commandId)
Returns true if the command is supported; otherwise, returns false.
document . queryCommandValue p535 (commandId)
Returns the value of the command, as described in the list below.
The execCommand(commandId, showUI, value) method on the HTMLDocument p71 interface allows scripts to
perform actions on the current selection p514 or at the current caret position. Generally, these commands would be
used to implement editor UI, for example having a "delete" button on a toolbar.
There are three variants to this method, with one, two, and three arguments respectively. The showUI and value
parameters, even if specified, are ignored except where otherwise stated.
When execCommand() p535 is invoked, the user agent must follow the following steps:
1.
If the given commandId maps to an entry in the list below whose "Enabled When" entry has a condition
that is currently false, do nothing; abort these steps.
2.
Otherwise, execute the "Action" listed below for the given commandId.
A document is ready for editing host commands if it has a selection that is entirely within an editing host p518 ,
or if it has no selection but its caret is inside an editing host p518 .
The queryCommandEnabled(commandId) method, when invoked, must return true if the condition listed below
under "Enabled When" for the given commandId is true, and false otherwise.
The queryCommandIndeterm(commandId) method, when invoked, must return true if the condition listed below
under "Indeterminate When" for the given commandId is true, and false otherwise.
The queryCommandState(commandId) method, when invoked, must return the value expressed below under
"State" for the given commandId.
The queryCommandSupported(commandId) method, when invoked, must return true if the given commandId is in
the list below, and false otherwise.
The queryCommandValue(commandId) method, when invoked, must return the value expressed below under
"Value" for the given commandId.
The possible values for commandId, and their corresponding meanings, are as follows. These values must be
compared to the argument in an ASCII case-insensitive p33 manner.
bold
Summary: Toggles whether the selection is bold.
535
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the b p175 element (or, again, unwrapped, or have that semantic inserted or removed, as
defined by the UA).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: True if the selection, or the caret, if there is no selection, is, or is contained within, a b p175 element.
False otherwise.
Value: The string "true" if the expression given for the "State" above is true, the string "false" otherwise.
createLink
Summary: Toggles whether the selection is a link or not. If the second argument is true, and a link is to be
added, the user agent will ask the user for the address. Otherwise, the third argument will be used as the
address.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the a p160 element (or, again, unwrapped, or have that semantic inserted or removed, as
defined by the UA). If the user agent creates an a p160 element or modifies an existing a p160 element, then if
the showUI argument is present and has the value false, then the value of the value argument must be used
as the URL p51 of the link. Otherwise, the user agent should prompt the user for the URL of the link.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
delete
Summary: Deletes the selection or the character before the cursor.
Action: The user agent must act as if the user had performed a backspace operation p519 .
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
formatBlock
Summary: Wraps the selection in the element given by the second argument. If the second argument
doesn't specify an element that is a formatBlock candidate, does nothing.
Action: The user agent must run the following steps:
1.
If the value argument wasn't specified, abort these steps without doing anything.
2.
If the value argument has a leading U+003C LESS-THAN SIGN character (<) and a trailing U+003E
GREATER-THAN SIGN character (>), then remove the first and last characters from value.
3.
If value is (now) an ASCII case-insensitive p33 match for the tag name of an element defined by this
specification that is defined to be a formatBlock candidate p536 , then, for every position in the
selection, take the nearest formatBlock candidate p536 ancestor element of that position that
contains only phrasing content p91 , and, if that element is editable p518 , is not an editing host p518 ,
and has a parent element whose content model allows that parent to contain any flow content p91 ,
replace it with an element in the HTML namespace whose name is value, and move all the children
that were in it to the new element, and copy all the attributes that were on it to the new element.
If there is no selection, then, where in the description above refers to the selection, the user agent
must act as if the selection was an empty range (with just one position) at the caret position.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
forwardDelete
Summary: Deletes the selection or the character after the cursor.
Action: The user agent must act as if the user had performed a forward delete operation p519 .
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertImage
Summary: Toggles whether the selection is an image or not. If the second argument is true, and an image is
to be added, the user agent will ask the user for the address. Otherwise, the third argument will be used as
the address.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the img p186 element (or, again, unwrapped, or have that semantic inserted or removed, as
defined by the UA). If the user agent creates an img p186 element or modifies an existing img p186 element, then
536
if the showUI argument is present and has the value false, then the value of the value argument must be
used as the URL p51 of the image. Otherwise, the user agent should prompt the user for the URL of the image.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertHTML
Summary: Replaces the selection with the value of the third argument parsed as HTML.
Action: The user agent must run the following steps:
1.
If the document is an XML document p71 , then throw an INVALID_ACCESS_ERR p70 exception and
abort these steps.
2.
If the value argument wasn't specified, abort these steps without doing anything.
3.
If there is a selection, act as if the user had requested that the selection be deleted p519 .
4.
Invoke the HTML fragment parsing algorithm p626 with an arbitrary orphan body p131 element owned
by the same Document p31 as the context p239 element and with the value argument as input p303 .
5.
Insert the nodes returned by the previous step into the document at the location of the caret, firing
any mutation events as appropriate.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertLineBreak
Summary: Inserts a line break.
Action: The user agent must act as if the user had requested a line separator p519 .
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertOrderedList
Summary: Toggles whether the selection is an ordered list.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the ol p152 element (or unwrapped, or, if there is no selection, have that semantic inserted or
removed — the exact behavior is UA-defined).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertUnorderedList
Summary: Toggles whether the selection is an unordered list.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the ul p153 element (or unwrapped, or, if there is no selection, have that semantic inserted or
removed — the exact behavior is UA-defined).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertParagraph
Summary: Inserts a paragraph break.
Action: The user agent must act as if the user had performed a break block p519 editing action.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
insertText
Summary: Inserts the text given in the third parameter.
Action: The user agent must act as if the user had inserted text p519 corresponding to the value parameter.
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
537
italic
Summary: Toggles whether the selection is italic.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the i p174 element (or, again, unwrapped, or have that semantic inserted or removed, as
defined by the UA).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: True if the selection, or the caret, if there is no selection, is, or is contained within, a i p174 element.
False otherwise.
Value: The string "true" if the expression given for the "State" above is true, the string "false" otherwise.
redo
Summary: Acts as if the user had requested a redo.
Action: The user agent must move forward one step p534 in its undo transaction history p532 , restoring the
associated state. If the undo position p533 is at the end of the undo transaction history p532 , the user agent
must do nothing. See the undo history p532 .
Enabled When: The undo position p533 is not at the end of the undo transaction history p532 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
selectAll
Summary: Selects all the editable content.
Action: The user agent must change the selection so that all the content in the currently focused editing
host p518 is selected. If no editing host p518 is focused, then the content of the entire document must be
selected.
Enabled When: Always.
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
subscript
Summary: Toggles whether the selection is subscripted.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the sub p174 element (or, again, unwrapped, or have that semantic inserted or removed, as
defined by the UA).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: True if the selection, or the caret, if there is no selection, is, or is contained within, a sub p174 element.
False otherwise.
Value: The string "true" if the expression given for the "State" above is true, the string "false" otherwise.
superscript
Summary: Toggles whether the selection is superscripted.
Action: The user agent must act as if the user had requested that the selection be wrapped in the
semantics p519 of the sup p174 element (or unwrapped, or, if there is no selection, have that semantic inserted
or removed — the exact behavior is UA-defined).
Enabled When: The document is ready for editing host commands p535 .
Indeterminate When: Never.
State: True if the selection, or the caret, if there is no selection, is, or is contained within, a sup p174 element.
False otherwise.
Value: The string "true" if the expression given for the "State" above is true, the string "false" otherwise.
undo
Summary: Acts as if the user had requested an undo.
Action: The user agent must move back one step p534 in its undo transaction history p532 , restoring the
associated state. If the undo position p533 is at the start of the undo transaction history p532 , the user agent
must do nothing. See the undo history p532 .
Enabled When: The undo position p533 is not at the start of the undo transaction history p532 .
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
unlink
Summary: Removes all links from the selection.
Action: The user agent must remove all a p160 elements that have href p383 attributes and that are partially or
completely included in the current selection.
Enabled When: The document has a selection that is entirely within an editing host p518 and that contains
(either partially or completely) at least one a p160 element that has an href p383 attribute.
Indeterminate When: Never.
State: Always false.
538
Value: Always the string "false".
unselect
Summary: Unselects everything.
Action: The user agent must change the selection so that nothing is selected.
Enabled When: Always.
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
vendorID-customCommandID
Action: User agents may implement vendor-specific extensions to this API. Vendor-specific extensions to the
list of commands should use the syntax vendorID-customCommandID so as to prevent clashes between
extensions from different vendors and future additions to this specification.
Enabled When: UA-defined.
Indeterminate When: UA-defined.
State: UA-defined.
Value: UA-defined.
Anything else
Action: User agents must do nothing.
Enabled When: Never.
Indeterminate When: Never.
State: Always false.
Value: Always the string "false".
539
9 Communication
9.1 Event definitions
Messages in server-sent events, Web sockets, cross-document messaging p540 , and channel messaging p543 use the
message event. [EVENTSOURCE] p701 [WEBSOCKET] p704
The following interface is defined for this event:
interface MessageEvent : Event {
readonly attribute any data;
readonly attribute DOMString origin;
readonly attribute DOMString lastEventId;
readonly attribute WindowProxy source;
readonly attribute MessagePortArray ports;
void initMessageEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean
cancelableArg, in any dataArg, in DOMString originArg, in DOMString lastEventIdArg, in
WindowProxy sourceArg, in MessagePortArray portsArg);
};
This box is non-normative. Implementation requirements are given below this box.
event . data
p540
Returns the data of the message.
event . origin p540
Returns the origin of the message, for server-sent events and cross-document messaging p540 .
event . lastEventId p540
Returns the last event ID, for server-sent events.
event . source p540
Returns the WindowProxy p449 of the source window, for cross-document messaging p540 .
event . ports p540
Returns the MessagePortArray p544 sent with the message, for cross-document messaging p540 and
channel messaging p543 .
The initMessageEvent() method must initialize the event in a manner analogous to the similarly-named method
in the DOM Events interfaces. [DOMEVENTS] p701
The data attribute represents the message being sent.
The origin attribute represents, in server-sent events and cross-document messaging p540 , the origin p449 of the
document that sent the message (typically the scheme, hostname, and port of the document, but not its path or
fragment identifier).
The lastEventId attribute represents, in server-sent events, the last event ID string of the event source.
The source attribute represents, in cross-document messaging p540 , the WindowProxy p449 of the browsing
context p439 of the Window p443 object from which the message came.
The ports attribute represents, in cross-document messaging p540 and channel messaging p543 the
MessagePortArray p544 being sent, if any.
Except where otherwise specified, when the user agent creates and dispatches a message p540 event in the
algorithms described in the following sections, the lastEventId p540 attribute must be the empty string, the
origin p540 attribute must be the empty string, the source p540 attribute must be null, and the ports p540 attribute
must be null.
9.2 Cross-document messaging
Web browsers, for security and privacy reasons, prevent documents in different domains from affecting each
other; that is, cross-site scripting is disallowed.
540
While this is an important security feature, it prevents pages from different domains from communicating even
when those pages are not hostile. This section introduces a messaging system that allows documents to
communicate with each other regardless of their source domain, in a way designed to not enable cross-site
scripting attacks.
The task source p490 for the tasks p489 in cross-document messaging p540 is the posted message task source.
9.2.1 Introduction
This section is non-normative.
For example, if document A contains an iframe p199 element that contains document B, and script in
document A calls postMessage() p542 on the Window p443 object of document B, then a message event will be
fired on that object, marked as originating from the Window p443 of document A. The script in document A
might look like:
var o = document.getElementsByTagName('iframe')[0];
o.contentWindow.postMessage('Hello world', 'http://b.example.org/');
To register an event handler for incoming events, the script would use addEventListener() (or similar
mechanisms). For example, the script in document B might look like:
window.addEventListener('message', receiver, false);
function receiver(e) {
if (e.origin == 'http://example.com') {
if (e.data == 'Hello world') {
e.source.postMessage('Hello', e.origin);
} else {
alert(e.data);
}
}
}
This script first checks the domain is the expected domain, and then looks at the message, which it either
displays to the user, or responds to by sending a message back to the document which sent the message in
the first place.
9.2.2 Security
9.2.2.1 Authors
⚠Warning! Use of this API requires extra care to protect users from hostile entities abusing a site for
their own purposes.
Authors should check the origin p540 attribute to ensure that messages are only accepted from domains that they
expect to receive messages from. Otherwise, bugs in the author's message handling code could be exploited by
hostile sites.
Furthermore, even after checking the origin p540 attribute, authors should also check that the data in question is of
the expected format. Otherwise, if the source of the event has been attacked using a cross-site scripting flaw,
further unchecked processing of information sent using the postMessage() p542 method could result in the attack
being propagated into the receiver.
Authors should not use the wildcard keyword (*) in the targetOrigin argument in messages that contain any
confidential information, as otherwise there is no way to guarantee that the message is only delivered to the
recipient to which it was intended.
9.2.2.2 User agents
The integrity of this API is based on the inability for scripts of one origin p449 to post arbitrary events (using
dispatchEvent() or otherwise) to objects in other origins (those that are not the same p451 ).
Note: Implementors are urged to take extra care in the implementation of this feature. It
allows authors to transmit information from one domain to another domain, which is normally
disallowed for security reasons. It also requires that UAs be careful to allow access to certain
properties but not others.
541
9.2.3 Posting messages
This box is non-normative. Implementation requirements are given below this box.
window . postMessage p542 (message, [ ports, ] targetOrigin)
Posts a message, optionally with an array of ports, to the given window.
If the origin of the target window doesn't match the given origin, the message is discarded, to avoid
information leakage. To send the message to the target regardless of origin, set the target origin to
"*". To restrict the message to same-origin targets only, without needing to explicitly state the origin,
set the target origin to "/".
Throws an INVALID_STATE_ERR p70 if the ports array is not null and it contains either null entries or
duplicate ports.
When a script invokes the postMessage(message, targetOrigin) method (with only two arguments) on a
Window p443 object, the user agent must follow these steps:
1.
If the value of the targetOrigin argument is neither a single U+002A ASTERISK character (*), a single
U+002F SOLIDUS character (/), nor an absolute URL p52 with a p51 component that is
either empty or a single U+002F SOLIDUS character (/), then throw a SYNTAX_ERR p70 exception and abort
the overall set of steps.
2.
Let message clone be the result of obtaining a structured clone p67 of the message argument. If this
throws an exception, then throw that exception and abort these steps.
3.
Return from the postMessage() p542 method, but asynchronously continue running these steps.
4.
If the targetOrigin argument is a single literal U+002F SOLIDUS character (/), and the Document p31 of the
Window p443 object on which the method was invoked does not have the same origin p451 as the entry
script p441 's document p488 , then abort these steps silently.
Otherwise, if the targetOrigin argument is an absolute URL p52 , and the Document p31 of the Window p443
object on which the method was invoked does not have the same origin p451 as targetOrigin, then abort
these steps silently.
Otherwise, the targetOrigin argument is a single literal U+002A ASTERISK character (*), and no origin
check is made.
5.
Create an event that uses the MessageEvent p540 interface, with the event name message p540 , which does
not bubble, is not cancelable, and has no default action. The data p540 attribute must be set to the value
of message clone, the origin p540 attribute must be set to the Unicode serialization p451 of the origin p449 of
the script that invoked the method, and the source p540 attribute must be set to the script's global
object p487 's WindowProxy p449 object.
6.
Queue a task p490 to dispatch the event created in the previous step at the Window p443 object on which the
method was invoked. The task source p490 for this task p489 is the posted message task source p541 .
9.2.4 Posting messages with message ports
When a script invokes the postMessage(message, targetOrigin, ports) method (with three arguments) on a
Window p443 object, the user agent must follow these steps:
542
1.
If the value of the targetOrigin argument is neither a single U+002A ASTERISK character (*), a single
U+002F SOLIDUS character (/), nor an absolute URL p52 with a p51 component that is
either empty or a single U+002F SOLIDUS character (/), then throw a SYNTAX_ERR p70 exception and abort
the overall set of steps.
2.
Let message clone be the result of obtaining a structured clone p67 of the message argument. If this
throws an exception, then throw that exception and abort these steps.
3.
If the ports argument is empty, then act as if the method had just been called with two arguments p542 ,
message and targetOrigin.
4.
If any of the entries in ports are null, if any MessagePort p544 object is listed in ports more than once, or if
any of the MessagePort p544 objects listed in ports have already been cloned once before, then throw an
INVALID_STATE_ERR p70 exception.
5.
Let new ports be an empty array.
For each port in ports in turn, obtain a new port by cloning p545 the port with the Window p443 object on
which the method was invoked as the owner of the clone, and append the clone to the new ports array.
6.
Return from the postMessage() p542 method, but asynchronously continue running these steps.
7.
If the targetOrigin argument is a single literal U+002F SOLIDUS character (/), and the Document p31 of the
Window p443 object on which the method was invoked does not have the same origin p451 as the entry
script p441 's document p488 , then abort these steps silently.
Otherwise, if the targetOrigin argument is an absolute URL p52 , and the Document p31 of the Window p443
object on which the method was invoked does not have the same origin p451 as targetOrigin, then abort
these steps silently.
Otherwise, the targetOrigin argument is a single literal U+002A ASTERISK character (*), and no origin
check is made.
8.
Create an event that uses the MessageEvent p540 interface, with the event name message p540 , which does
not bubble, is not cancelable, and has no default action. The data p540 attribute must be set to the value
of message clone, the origin p540 attribute must be set to the Unicode serialization p451 of the origin p449 of
the script that invoked the method, and the source p540 attribute must be set to the script's global
object p487 's WindowProxy p449 object.
9.
Let the ports p540 attribute of the event be the new ports array.
10.
Queue a task p490 to dispatch the event created in the previous step at the Window p443 object on which the
method was invoked. The task source p490 for this task p489 is the posted message task source p541 .
Note: These steps, with the exception of the third, fourth, and fifth steps and the penultimate
step, are identical to those in the previous section.
9.3 Channel messaging
9.3.1 Introduction
This section is non-normative.
To enable independent pieces of code (e.g. running in different browsing contexts p439 ) to communicate directly,
authors can use channel messaging p543 .
Communication channels in this mechanisms are implemented as two-ways pipes, with a port at each end.
Messages sent in one port are delivered at the other port, and vice-versa. Messages are asynchronous, and
delivered as DOM events.
To create a connection (two "entangled" ports), the MessageChannel() constructor is called:
var channel = new MessageChannel();
One of the ports is kept as the local port, and the other port is sent to the remote code, e.g. using
postMessage() p542 :
otherWindow.postMessage('hello', 'http://example.com', [channel.port2]);
To send messages, the postMessage() p545 method on the port is used:
channel.port1.postMessage('hello');
To receive messages, one listens to message p540 events:
channel.port1.onmessage = handleMessage;
function handleMessage(event) {
// message is in event.data
// ...
}
9.3.2 Message channels
[Constructor]
interface MessageChannel {
readonly attribute MessagePort port1;
readonly attribute MessagePort port2;
};
543
This box is non-normative. Implementation requirements are given below this box.
channel = new MessageChannel p544 ()
Returns a new MessageChannel p543 object with two new MessagePort p544 objects.
channel . port1
Returns the first MessagePort p544 object.
channel . port2
Returns the second MessagePort p544 object.
When the MessageChannel() constructor is called, it must run the following algorithm:
1.
Create a new MessagePort object p545 owned by the script's global object p487 , and let port1 be that
object.
2.
Create a new MessagePort object p545 owned by the script's global object p487 , and let port2 be that
object.
3.
Entangle p545 the port1 and port2 objects.
4.
Instantiate a new MessageChannel p543 object, and let channel be that object.
5.
Let the port1 p544 attribute of the channel object be port1.
6.
Let the port2 p544 attribute of the channel object be port2.
7.
Return channel.
This constructor must be visible when the script's global object p487 is either a Window p443 object or an object
implementing the WorkerUtils interface.
The port1 and port2 attributes must return the values they were assigned when the MessageChannel p543 object
was created.
9.3.3 Message ports
Each channel has two message ports. Data sent through one port is received by the other port, and vice versa.
typedef sequence MessagePortArray;
interface MessagePort {
void postMessage(in any message, in optional MessagePortArray ports);
void start();
void close();
// event handlers
attribute Function onmessage;
};
MessagePort implements EventTarget;
This box is non-normative. Implementation requirements are given below this box.
port . postMessage(message [, ports] )
Posts a message through the channel, optionally with the given ports.
Throws an INVALID_STATE_ERR p70 if the ports array is not null and it contains either null entries,
duplicate ports, or the source or target port.
port . start p546 ()
Begins dispatching messages received on the port.
port . close p546 ()
Disconnects the port, so that it is no longer active.
Each MessagePort p544 object can be entangled with another (a symmetric relationship). Each MessagePort p544
object also has a task source p490 called the port message queue, initial empty. A port message queue p544 can be
544
enabled or disabled, and is initially disabled. Once enabled, a port can never be disabled again (though messages
in the queue can get moved to another queue or removed altogether, which has much the same effect).
When the user agent is to create a new MessagePort object owned by a script's global object p487 object owner,
it must instantiate a new MessagePort p544 object, and let its owner be owner.
When the user agent is to entangle two MessagePort p544 objects, it must run the following steps:
1.
If one of the ports is already entangled, then disentangle it and the port that it was entangled with.
Note: If those two previously entangled ports were the two ports of a
MessageChannel p543 object, then that MessageChannel p543 object no longer represents an
actual channel: the two ports in that object are no longer entangled.
2.
Associate the two ports to be entangled, so that they form the two parts of a new channel. (There is no
MessageChannel p543 object that represents this channel.)
When the user agent is to clone a port original port, with the clone being owned by owner, it must run the
following steps, which return a new MessagePort p544 object. These steps must be run atomically.
1.
Create a new MessagePort object p545 owned by owner, and let new port be that object.
2.
Move all the events in the port message queue p544 of original port to the port message queue p544 of new
port, if any, leaving the new port's port message queue p544 in its initial disabled state.
3.
If the original port is entangled with another port, then run these substeps:
4.
1.
Let the remote port be the port with which the original port is entangled.
2.
Entangle p545 the remote port and new port objects. The original port object will be
disentangled by this process.
Return new port. It is the clone.
The postMessage() method, when called on a port source port, must cause the user agent to run the following
steps:
1.
Let target port be the port with which source port is entangled, if any.
2.
If the method was called with a second argument ports and that argument isn't null, then, if any of the
entries in ports are null, if any MessagePort p544 object is listed in ports more than once, if any of the
MessagePort p544 objects listed in ports have already been cloned once before, or if any of the entries in
ports are either the source port or the target port (if any), then throw an INVALID_STATE_ERR p70
exception.
3.
If there is no target port (i.e. if source port is not entangled), then abort these steps.
4.
Create an event that uses the MessageEvent p540 interface, with the name message p540 , which does not
bubble, is not cancelable, and has no default action.
5.
Let message be the method's first argument.
6.
Let message clone be the result of obtaining a structured clone p67 of message. If this throws an
exception, then throw that exception and abort these steps.
7.
Let the data p540 attribute of the event have the value of message clone.
8.
If the method was called with a second argument ports and that argument isn't null, then run the
following substeps:
1.
Let new ports be an empty array.
For each port in ports in turn, obtain a new port by cloning p545 the port with the owner of the
target port as the owner of the clone, and append the clone to the new ports array.
Note: If the original ports array was empty, then the new ports array will
also be empty.
2.
9.
Let the ports p540 attribute of the event be the new ports array.
Add the event to the port message queue p544 of target port.
545
The start() method must enable its port's port message queue p544 , if it is not already enabled.
When a port's port message queue p544 is enabled, the event loop p489 must use it as one of its task sources p490 .
Note: If the Document p31 of the port's event listeners' global object p487 is not fully active p440 ,
then the messages are lost.
The close() method, when called on a port local port that is entangled with another port, must cause the user
agents to disentangle the two ports. If the method is called on a port that is not entangled, then the method must
do nothing.
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported, as IDL attributes, by all objects implementing the MessagePort p544 interface:
Event handler p492 Event handler event type p493
onmessage
message p540
The first time a MessagePort p544 object's onmessage p546 IDL attribute is set, the port's port message queue p544
must be enabled, as if the start() p546 method had been called.
9.3.3.1 Ports and garbage collection
When a MessagePort p544 object o is entangled, user agents must either act as if o's entangled MessagePort p544
object has a strong reference to o, or as if o's owner has a strong reference to o.
Thus, a message port can be received, given an event listener, and then forgotten, and so
long as that event listener could receive a message, the channel will be maintained.
Of course, if this was to occur on both sides of the channel, then both ports could be garbage
collected, since they would not be reachable from live code, despite having a strong reference
to each other.
Furthermore, a MessagePort p544 object must not be garbage collected while there exists a message in a task
queue p489 that is to be dispatched on that MessagePort p544 object, or while the MessagePort p544 object's port
message queue p544 is open and there exists a message p540 event in that queue.
Note: Authors are strongly encouraged to explicitly close MessagePort p544 objects to
disentangle them, so that their resources can be recollected. Creating many MessagePort p544
objects and discarding them without closing them can lead to high memory usage.
546
10 The HTML syntax
Note: This section only describes the rules for resources labeled with an HTML MIME type p26 .
Rules for XML resources are discussed in the section below entitled "The XHTML syntax p635 ".
10.1 Writing HTML documents
This section only applies to documents, authoring tools, and markup generators. In particular, it does not apply to
conformance checkers; conformance checkers must use the requirements given in the next section ("parsing
HTML documents").
Documents must consist of the following parts, in the given order:
1.
Optionally, a single U+FEFF BYTE ORDER MARK (BOM) character.
2.
Any number of comments p554 and space characters p34 .
3.
A DOCTYPE p547 .
4.
Any number of comments p554 and space characters p34 .
5.
The root element, in the form of an html p106 element p548 .
6.
Any number of comments p554 and space characters p34 .
The various types of content mentioned above are described in the next few sections.
In addition, there are some restrictions on how character encoding declarations p118 are to be serialized, as
discussed in the section on that topic.
Space characters before the root html p106 element, and space characters at the start of the
html p106 element and before the head p106 element, will be dropped when the document is
parsed; space characters after the root html p106 element will be parsed as if they were at the
end of the body p131 element. Thus, space characters around the root element do not round-trip.
It is suggested that newlines be inserted after the DOCTYPE, after any comments that are
before the root element, after the html p106 element's start tag (if it is not omitted p551 ), and
after any comments that are inside the html p106 element but before the head p106 element.
Many strings in the HTML syntax (e.g. the names of elements and their attributes) are case-insensitive, but only
for characters in the ranges U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and
U+0061 to U+007A (LATIN SMALL LETTER A to LATIN SMALL LETTER Z). For convenience, in this section this is just
referred to as "case-insensitive".
10.1.1 The DOCTYPE
A DOCTYPE is a required preamble.
Note: DOCTYPEs are required for legacy reasons. When omitted, browsers tend to use a
different rendering mode that is incompatible with some specifications. Including the
DOCTYPE in a document ensures that the browser makes a best-effort attempt at following the
relevant specifications.
A DOCTYPE must consist of the following characters, in this order:
1.
2.
3.
4.
5.
6.
A string that is an ASCII case-insensitive p33 match for the string ").
Note: In other words, , case-insensitively.
For the purposes of HTML generators that cannot output HTML markup with the short DOCTYPE "", a DOCTYPE legacy string may be inserted into the DOCTYPE (in the position defined above). This string
must consist of:
547
1.
2.
3.
4.
5.
6.
One or more space characters p34 .
A string that is an ASCII case-insensitive p33 match for the string "SYSTEM".
One or more space characters p34 .
A U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (the quote mark).
The literal string "about:legacy-compat p52 ".
A matching U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (i.e. the same character as in
the earlier step labeled quote mark).
Note: In other words, or , case-insensitively except for the bit in single or double quotes.
The DOCTYPE legacy string p547 should not be used unless the document is generated from a system that cannot
output the shorter string.
To help authors transition from HTML4 and XHTML1, an obsolete permitted DOCTYPE string can be inserted
into the DOCTYPE (in the position defined above). This string must consist of:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
One or more space characters p34 .
A string that is an ASCII case-insensitive p33 match for the string "PUBLIC".
One or more space characters p34 .
A U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (the first quote mark).
The string from one of the cells in the first column of the table below. The row to which this cell belongs
is the selected row.
A matching U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (i.e. the same character as in
the earlier step labeled first quote mark).
If the cell in the second column of the selected row is not blank, one or more space characters p34 .
If the cell in the second column of the selected row is not blank, a U+0022 QUOTATION MARK or U+0027
APOSTROPHE character (the third quote mark).
If the cell in the second column of the selected row is not blank, the string from the cell in the second
column of the selected row.
If the cell in the second column of the selected row is not blank, a matching U+0022 QUOTATION MARK
or U+0027 APOSTROPHE character (i.e. the same character as in the earlier step labeled third quote
mark).
Allowed values for public and system identifiers in an obsolete permitted DOCTYPE string p548 .
Public identifier
System identifier
-//W3C//DTD HTML 4.0//EN
-//W3C//DTD HTML 4.0//EN
http://www.w3.org/TR/REC-html40/strict.dtd
-//W3C//DTD HTML 4.01//EN
-//W3C//DTD HTML 4.01//EN
http://www.w3.org/TR/html4/strict.dtd
-//W3C//DTD XHTML 1.0 Strict//EN http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd
-//W3C//DTD XHTML 1.1//EN
http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd
A DOCTYPE p547 containing an obsolete permitted DOCTYPE string p548 is an obsolete permitted DOCTYPE.
Authors should not use obsolete permitted DOCTYPEs p548 , as they are unnecessarily long.
10.1.2 Elements
There are five different kinds of elements: void elements p548 , raw text elements p548 , RCDATA elements p548 , foreign
elements p548 , and normal elements p548 .
Void elements
area p266 , base p108 , br p181 , col p279 , command p371 , embed p205 , hr p149 , img p186 , input p303 , keygen p344 , link p109 ,
meta p112 , param p213 , source p217 , wbr p181
Raw text elements
script p122 , style p119
RCDATA elements
textarea p341 , title p107
Foreign elements
Elements from the MathML namespace p70 and the SVG namespace p70 .
Normal elements
All other allowed HTML elements p26 are normal elements.
Tags are used to delimit the start and end of elements in the markup. Raw text p548 , RCDATA p548 , and normal p548
elements have a start tag p549 to indicate where they begin, and an end tag p550 to indicate where they end. The
start and end tags of certain normal elements p548 can be omitted p551 , as described later. Those that cannot be
omitted must not be omitted. Void elements p548 only have a start tag; end tags must not be specified for void
elements p548 . Foreign elements p548 must either have a start tag and an end tag, or a start tag that is marked as
self-closing, in which case they must not have an end tag.
548
The contents of the element must be placed between just after the start tag (which might be implied, in certain
cases p551 ) and just before the end tag (which again, might be implied in certain cases p551 ). The exact allowed
contents of each individual element depends on the content model of that element, as described earlier in this
specification. Elements must not contain content that their content model disallows. In addition to the restrictions
placed on the contents by those content models, however, the five types of elements have additional syntactic
requirements.
Void elements p548 can't have any contents (since there's no end tag, no content can be put between the start tag
and the end tag).
Raw text elements p548 can have text p553 , though it has restrictions p552 described below.
RCDATA elements p548 can have text p553 and character references p553 , but the text must not contain an ambiguous
ampersand p553 . There are also further restrictions p552 described below.
Foreign elements p548 whose start tag is marked as self-closing can't have any contents (since, again, as there's no
end tag, no content can be put between the start tag and the end tag). Foreign elements p548 whose start tag is not
marked as self-closing can have text p553 , character references p553 , CDATA sections p553 , other elements p548 , and
comments p554 , but the text must not contain the character U+003C LESS-THAN SIGN (<) or an ambiguous
ampersand p553 .
The HTML syntax does not support namespace declarations, even in foreign elements p548 .
For instance, consider the following HTML fragment:
The innermost element, cdr:license, is actually in the SVG namespace, as the "xmlns:cdr"
attribute has no effect (unlike in XML). In fact, as the comment in the fragment above says,
the fragment is actually non-conforming. This is because the SVG specification does not define
any elements called "cdr:license" in the SVG namespace.
Normal elements p548 can have text p553 , character references p553 , other elements p548 , and comments p554 , but the
text must not contain the character U+003C LESS-THAN SIGN (<) or an ambiguous ampersand p553 . Some normal
elements p548 also have yet more restrictions p552 on what content they are allowed to hold, beyond the restrictions
imposed by the content model and those described in this paragraph. Those restrictions are described below.
Tags contain a tag name, giving the element's name. HTML elements all have names that only use characters in
the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0061 LATIN SMALL LETTER A to U+007A LATIN
SMALL LETTER Z, and U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z. In the HTML syntax,
tag names, even those for foreign elements p548 , may be written with any mix of lower- and uppercase letters that,
when converted to all-lowercase, matches the element's tag name; tag names are case-insensitive.
10.1.2.1 Start tags
Start tags must have the following format:
1.
The first character of a start tag must be a U+003C LESS-THAN SIGN character (<).
2.
The next few characters of a start tag must be the element's tag name p549 .
3.
If there are to be any attributes in the next step, there must first be one or more space characters p34 .
4.
Then, the start tag may have a number of attributes, the syntax for which p550 is described below.
Attributes may be separated from each other by one or more space characters p34 .
5.
After the attributes, or after the tag name p549 if there are no attributes, there may be one or more space
characters p34 . (Some attributes are required to be followed by a space. See the attributes section p550
below.)
6.
Then, if the element is one of the void elements p548 , or if the element is a foreign element p548 , then there
may be a single U+002F SOLIDUS character (/). This character has no effect on void elements p548 , but on
foreign elements p548 it marks the start tag as self-closing.
7.
Finally, start tags must be closed by a U+003E GREATER-THAN SIGN character (>).
549
10.1.2.2 End tags
End tags must have the following format:
1.
The first character of an end tag must be a U+003C LESS-THAN SIGN character (<).
2.
The second character of an end tag must be a U+002F SOLIDUS character (/).
3.
The next few characters of an end tag must be the element's tag name p549 .
4.
After the tag name, there may be one or more space characters p34 .
5.
Finally, end tags must be closed by a U+003E GREATER-THAN SIGN character (>).
10.1.2.3 Attributes
Attributes for an element are expressed inside the element's start tag.
Attributes have a name and a value. Attribute names must consist of one or more characters other than the
space characters p34 , U+0000 NULL, U+0022 QUOTATION MARK ("), U+0027 APOSTROPHE ('), U+003E GREATERTHAN SIGN (>), U+002F SOLIDUS (/), and U+003D EQUALS SIGN (=) characters, the control characters, and any
characters that are not defined by Unicode. In the HTML syntax, attribute names, even those for foreign
elements p548 , may be written with any mix of lower- and uppercase letters that are an ASCII case-insensitive p33
match for the attribute's name.
Attribute values are a mixture of text p553 and character references p553 , except with the additional restriction that
the text cannot contain an ambiguous ampersand p553 .
Attributes can be specified in four different ways:
Empty attribute syntax
Just the attribute name p550 . The value is implicitly the empty string.
In the following example, the disabled p354 attribute is given with the empty attribute syntax:
Hello
Hello
10.1.2.6 Restrictions on the contents of raw text and RCDATA elements
The text in raw text p548 and RCDATA elements p548 must not contain any occurrences of the string "), or U+002F SOLIDUS (/).
10.1.3 Text
Text is allowed inside elements, attributes, and comments. Text must consist of Unicode characters. Text must not
contain U+0000 characters. Text must not contain permanently undefined Unicode characters (noncharacters).
Text must not contain control characters other than space characters p34 . Extra constraints are placed on what is
and what is not allowed in text based on where the text is to be put, as described in the other sections.
10.1.3.1 Newlines
Newlines in HTML may be represented either as U+000D CARRIAGE RETURN (CR) characters, U+000A LINE FEED
(LF) characters, or pairs of U+000D CARRIAGE RETURN (CR), U+000A LINE FEED (LF) characters in that order.
Where character references p553 are allowed, a character reference of a U+000A LINE FEED (LF) character (but not
a U+000D CARRIAGE RETURN (CR) character) also represents a newline p553 .
10.1.4 Character references
In certain cases described in other sections, text p553 may be mixed with character references. These can be
used to escape characters that couldn't otherwise legally be included in text p553 .
Character references must start with a U+0026 AMPERSAND character (&). Following this, there are three possible
kinds of character references:
Named character references
The ampersand must be followed by one of the names given in the named character references p627 section,
using the same case. The name must be one that is terminated by a U+003B SEMICOLON character (;).
Decimal numeric character reference
The ampersand must be followed by a U+0023 NUMBER SIGN character (#), followed by one or more digits
in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), representing a base-ten integer that
corresponds to a Unicode code point that is allowed according to the definition below. The digits must then
be followed by a U+003B SEMICOLON character (;).
Hexadecimal numeric character reference
The ampersand must be followed by a U+0023 NUMBER SIGN character (#), which must be followed by
either a U+0078 LATIN SMALL LETTER X character (x) or a U+0058 LATIN CAPITAL LETTER X character (X),
which must then be followed by one or more digits in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT
NINE (9), U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F, and U+0041 LATIN CAPITAL
LETTER A to U+0046 LATIN CAPITAL LETTER F, representing a base-sixteen integer that corresponds to a
Unicode code point that is allowed according to the definition below. The digits must then be followed by a
U+003B SEMICOLON character (;).
The numeric character reference forms described above are allowed to reference any Unicode code point other
than U+0000, U+000D, permanently undefined Unicode characters (noncharacters), and control characters other
than space characters p34 .
An ambiguous ampersand is a U+0026 AMPERSAND character (&) that is followed by one or more characters in
the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0061 LATIN SMALL LETTER A to U+007A LATIN
SMALL LETTER Z, and U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z, followed by a
U+003B SEMICOLON character (;), where these characters do not match any of the names given in the named
character references p627 section.
10.1.5 CDATA sections
CDATA sections must start with the character sequence U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK,
U+005B LEFT SQUARE BRACKET, U+0043 LATIN CAPITAL LETTER C, U+0044 LATIN CAPITAL LETTER D, U+0041
LATIN CAPITAL LETTER A, U+0054 LATIN CAPITAL LETTER T, U+0041 LATIN CAPITAL LETTER A, U+005B LEFT
SQUARE BRACKET (). Finally, the CDATA section must be ended
by the three character sequence U+005D RIGHT SQUARE BRACKET, U+005D RIGHT SQUARE BRACKET, U+003E
GREATER-THAN SIGN (]]>).
CDATA sections can only be used in foreign content (MathML or SVG). In this example, a CDATA section is
used to escape the contents of an ms element:
553
You can add a string to a number, but this stringifies the number:
+
3
=
10.1.6 Comments
Comments must start with the four character sequence U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK,
U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS ().
10.2 Parsing HTML documents
This section only applies to user agents, data mining tools, and conformance checkers.
Note: The rules for parsing XML documents into DOM trees are covered by the next section,
entitled "The XHTML syntax p635 ".
For HTML documents p71 , user agents must use the parsing rules described in this section to generate the DOM
trees. Together, these rules define what is referred to as the HTML parser.
While the HTML syntax described in this specification bears a close resemblance to SGML and
XML, it is a separate language with its own parsing rules.
Some earlier versions of HTML (in particular from HTML2 to HTML4) were based on SGML and
used SGML parsing rules. However, few (if any) web browsers ever implemented true SGML
parsing for HTML documents; the only user agents to strictly handle HTML as an SGML
application have historically been validators. The resulting confusion — with validators
claiming documents to have one representation while widely deployed Web browsers
interoperably implemented a different representation — has wasted decades of productivity.
This version of HTML thus returns to a non-SGML basis.
Authors interested in using SGML tools in their authoring pipeline are encouraged to use XML
tools and the XML serialization of HTML.
This specification defines the parsing rules for HTML documents, whether they are syntactically correct or not.
Certain points in the parsing algorithm are said to be parse errors. The error handling for parse errors is welldefined: user agents must either act as described below when encountering such problems, or must abort
processing at the first error that they encounter for which they do not wish to apply the rules described below.
Conformance checkers must report at least one parse error condition to the user if one or more parse error
conditions exist in the document and must not report parse error conditions if none exist in the document.
Conformance checkers may report more than one parse error condition if more than one parse error condition
exists in the document. Conformance checkers are not required to recover from parse errors.
Note: Parse errors are only errors with the syntax of HTML. In addition to checking for parse
errors, conformance checkers will also verify that the document obeys all the other
conformance requirements described in this specification.
For the purposes of conformance checkers, if a resource is determined to be in the HTML syntax p547 , then it is an
HTML document p71 .
10.2.1 Overview of the parsing model
The input to the HTML parsing process consists of a stream of Unicode characters, which is passed through a
tokenization p566 stage followed by a tree construction p589 stage. The output is a Document p31 object.
554
Note: Implementations that do not support scripting p29 do not have to actually create a DOM
Document p31 object, but the DOM tree in such cases is still used as the model for the rest of the
specification.
In the common case, the data handled by the tokenization stage comes from the network, but it can also come
from script p99 , e.g. using the document.write() p101 API.
There is only one set of states for the tokenizer stage and the tree construction stage, but the tree construction
stage is reentrant, meaning that while the tree construction stage is handling one token, the tokenizer might be
resumed, causing further tokens to be emitted and processed before the first token's processing is complete.
In the following example, the tree construction stage will be called upon to handle a "p" start tag token
while handling the "script" start tag token:
...
...
To handle these cases, parsers have a script nesting level, which must be initially set to zero, and a parser
pause flag, which must be initially set to false.
10.2.2 The input stream
The stream of Unicode characters that comprises the input to the tokenization stage will be initially seen by the
user agent as a stream of bytes (typically coming over the network or from the local file system). The bytes
encode the actual characters according to a particular character encoding, which the user agent must use to
decode the bytes into characters.
555
Note: For XML documents, the algorithm user agents must use to determine the character
encoding is given by the XML specification. This section does not apply to XML documents.
[XML] p705
10.2.2.1 Determining the character encoding
In some cases, it might be impractical to unambiguously determine the encoding before parsing the document.
Because of this, this specification provides for a two-pass mechanism with an optional pre-scan. Implementations
are allowed, as described below, to apply a simplified parsing algorithm to whatever bytes they have available
before beginning to parse the document. Then, the real parser is started, using a tentative encoding derived from
this pre-parse and other out-of-band metadata. If, while the document is being loaded, the user agent discovers an
encoding declaration that conflicts with this information, then the parser can get reinvoked to perform a parse of
the document with the real encoding.
User agents must use the following algorithm (the encoding sniffing algorithm) to determine the character
encoding to use when decoding a document in the first pass. This algorithm takes as input any out-of-band
metadata available to the user agent (e.g. the Content-Type metadata p57 of the document) and all the bytes
available so far, and returns an encoding and a confidence. The confidence is either tentative, certain, or
irrelevant. The encoding used, and whether the confidence in that encoding is tentative or certain, is used during
the parsing p596 to determine whether to change the encoding p561 . If no encoding is necessary, e.g. because the
parser is operating on a stream of Unicode characters and doesn't have to use an encoding at all, then the
confidence p556 is irrelevant.
1.
If the transport layer specifies an encoding, and it is supported, return that encoding with the
confidence p556 certain, and abort these steps.
2.
The user agent may wait for more bytes of the resource to be available, either in this step or at any later
step in this algorithm. For instance, a user agent might wait 500ms or 512 bytes, whichever came first.
In general preparsing the source to find the encoding improves performance, as it reduces the need to
throw away the data structures used when parsing upon finding the encoding information. However, if
the user agent delays too long to obtain data to determine the encoding, then the cost of the delay
could outweigh any performance improvements from the preparse.
3.
For each of the rows in the following table, starting with the first one and going down, if there are as
many or more bytes available than the number of bytes in the first column, and the first bytes of the file
match the bytes given in the first column, then return the encoding given in the cell in the second
column of that row, with the confidence p556 certain, and abort these steps:
Bytes in Hexadecimal Encoding
FE FF
UTF-16BE
FF FE
UTF-16LE
EF BB BF
UTF-8
Note: This step looks for Unicode Byte Order Marks (BOMs).
4.
Otherwise, the user agent will have to search for explicit character encoding information in the file itself.
This should proceed as follows:
Let position be a pointer to a byte in the input stream, initially pointing at the first byte. If at any point
during these substeps the user agent either runs out of bytes or decides that scanning further bytes
would not be efficient, then skip to the next step of the overall character encoding detection algorithm.
User agents may decide that scanning any bytes is not efficient, in which case these substeps are
entirely skipped.
Now, repeat the following "two" steps until the algorithm aborts (either because user agent aborts, as
described above, or because a character encoding is found):
1.
If position points to:
↪ A sequence of bytes starting with: 0x3C 0x21 0x2D 0x2D (ASCII '' sequence) and comes after the
0x3C byte that was found. (The two 0x2D bytes can be the same as the those in the
' (U+002D
HYPHEN-MINUS, U+002D HYPHEN-MINUS, U+003E GREATER-THAN SIGN).
↪ If current node is a ProcessingInstruction
Append the literal string ).
↪ If current node is a DocumentType
Append the literal string (U+003E GREATERTHAN SIGN).
Other node types (e.g. Attr) cannot occur as children of elements. If, despite this, they
somehow do occur, this algorithm must raise an INVALID_STATE_ERR p70 exception.
3.
The result of the algorithm is the string s.
Escaping a string (for the purposes of the algorithm above) consists of replacing any occurrences of the "&"
character by the string "&", any occurrences of the U+00A0 NO-BREAK SPACE character by the string
" ", and, if the algorithm was invoked in the attribute mode, any occurrences of the """ character by the
string """, or if it was not, any occurrences of the "<" character by the string "<", any occurrences of the
">" character by the string ">".
Note: Entity reference nodes are assumed to be expanded p30 by the user agent, and are
therefore not covered in the algorithm above.
Note: It is possible that the output of this algorithm, if parsed with an HTML parser p554 , will
not return the original tree structure. For instance, if a textarea p341 element to which a Comment
node has been appended is serialized and the output is then reparsed, the comment will end
up being displayed in the text field. Similarly, if, as a result of DOM manipulation, an element
contains a comment that contains the literal string "-->", then when the result of serializing
the element is parsed, the comment will be truncated at that point and the rest of the
comment will be interpreted as markup. More examples would be making a script p122 element
contain a text node with the text string "", or having a p p148 element that contains a
ul p153 element (as the ul p153 element's start tag p549 would imply the end tag for the p p148 ).
10.4 Parsing HTML fragments
The following steps form the HTML fragment parsing algorithm. The algorithm optionally takes as input an
Element p31 node, referred to as the context element, which gives the context for the parser, as well as input, a
string to parse, and returns a list of zero or more nodes.
Note: Parts marked fragment case in algorithms in the parser section are parts that only occur
if the parser was created for the purposes of this algorithm (and with a context element). The
algorithms have been annotated with such markings for informational purposes only; such
markings have no normative weight. If it is possible for a condition described as a fragment
case p626 to occur even when the parser wasn't created for the purposes of handling this
algorithm, then that is an error in the specification.
1.
Create a new Document p31 node, and mark it as being an HTML document p71 .
2.
If there is a context element, and the Document p31 of the context element is in quirks mode p75 , then let
the Document p31 be in quirks mode p75 . Otherwise, if there is a context element, and the Document p31 of
the context element is in limited-quirks mode p75 , then let the Document p31 be in limited-quirks mode p75 .
Otherwise, leave the Document p31 in no-quirks mode p75 .
3.
Create a new HTML parser p554 , and associate it with the just created Document p31 node.
4.
If there is a context element, run these substeps:
1.
Set the state of the HTML parser p554 's tokenization p566 stage as follows:
p107
or textarea p341 element
↪ If it is a title
Switch the tokenizer to the RCDATA state p566 .
p119
, xmp p661 , iframe p199 , noembed p661 , or noframes p661 element
↪ If it is a style
Switch the tokenizer to the RAWTEXT state p567 .
p122
element
↪ If it is a script
Switch the tokenizer to the script data state p567 .
p129
element
↪ If it is a noscript
If the scripting flag p565 is enabled, switch the tokenizer to the RAWTEXT state p567 .
Otherwise, leave the tokenizer in the data state p566 .
p661
element
↪ If it is a plaintext
Switch the tokenizer to the PLAINTEXT state p567 .
626
↪ Otherwise
Leave the tokenizer in the data state p566 .
Note: For performance reasons, an implementation that does not report
errors and that uses the actual state machine described in this specification
directly could use the PLAINTEXT state instead of the RAWTEXT and script
data states where those are mentioned in the list above. Except for rules
regarding parse errors, they are equivalent, since there is no appropriate
end tag token p566 in the fragment case, yet they involve far fewer state
transitions.
2.
Let root be a new html p106 element with no attributes.
3.
Append the element root to the Document p31 node created above.
4.
Set up the parser's stack of open elements p563 so that it contains just the single element root.
5.
Reset the parser's insertion mode appropriately p562 .
Note: The parser will reference the context element as part of that
algorithm.
6.
Set the parser's form element pointer p565 to the nearest node to the context element that is a
form p297 element (going straight up the ancestor chain, and including the element itself, if it is
a form p297 element), or, if there is no such form p297 element, to null.
5.
Place into the input stream p555 for the HTML parser p554 just created the input. The encoding
confidence p556 is irrelevant.
6.
Start the parser and let it run until it has consumed all the characters just inserted into the input stream.
7.
If there is a context element, return the child nodes of root, in tree order p27 .
Otherwise, return the children of the Document p31 object, in tree order p27 .
10.5 Named character references
This table lists the character reference names that are supported by HTML, and the code points to which they
refer. It is referenced by the previous sections.
Name
Character Glyph
Name
Character Glyph
Name
Character Glyph
AElig;
U+000C6
Æ
Cacute;
U+00106
Ć
Dcy;
U+00414
AElig
U+000C6
Æ
Cap;
U+022D2
?
Del;
U+02207
Д
∇
AMP;
U+00026
&
CapitalDifferentialD;
U+02145
ⅅ
Delta;
U+00394
Δ
AMP
U+00026
&
Cayleys;
U+0212D
ℭ
Dfr;
U+1D507
?
Aacute;
U+000C1
Á
Ccaron;
U+0010C
Č
DiacriticalAcute;
U+000B4
´
Aacute
U+000C1
Á
Ccedil;
U+000C7
Ç
DiacriticalDot;
U+002D9
˙
U+000C7
Ç
DiacriticalDoubleAcute;
U+002DD
˝
Abreve;
U+00102
Ă
Ccedil
Acirc;
U+000C2
Â
Ccirc;
U+00108
Ĉ
DiacriticalGrave;
U+00060
`
Acirc
U+000C2
Â
Cconint;
U+02230
∰
DiacriticalTilde;
U+002DC
˜
Acy;
U+00410
А
Cdot;
U+0010A
Ċ
Diamond;
U+022C4
⋄
Afr;
U+1D504
?
Cedilla;
U+000B8
¸
DifferentialD;
U+02146
ⅆ
Agrave;
U+000C0
À
CenterDot;
U+000B7
·
Dopf;
U+1D53B
𝔻
Agrave
U+000C0
À
Cfr;
U+0212D
ℭ
Dot;
U+000A8
¨
Alpha;
U+00391
Α
Chi;
U+003A7
Χ
DotDot;
U+020DC
◌?
Amacr;
U+00100
Ā
CircleDot;
U+02299
⊙
DotEqual;
U+02250
≐
And;
U+02A53
?
CircleMinus;
U+02296
⊖
DoubleContourIntegral;
U+0222F
∯
Aogon;
U+00104
Ą
CirclePlus;
U+02295
⊕
DoubleDot;
U+000A8
¨
Aopf;
U+1D538
𝔸
CircleTimes;
U+02297
⊗
DoubleDownArrow;
U+021D3
⇓
ApplyFunction;
U+02061
ClockwiseContourIntegral;
U+02232
∲
DoubleLeftArrow;
U+021D0
⇐
Aring;
U+000C5
Å
CloseCurlyDoubleQuote;
U+0201D
”
DoubleLeftRightArrow;
U+021D4
⇔
Aring
U+000C5
Å
CloseCurlyQuote;
U+02019
’
DoubleLeftTee;
U+02AE4
?
Ascr;
U+1D49C
?
Colon;
U+02237
∷
DoubleLongLeftArrow;
U+027F8
⟸
Assign;
U+02254
≔
Colone;
U+02A74
?
DoubleLongLeftRightArrow;
U+027FA
⟺
Atilde;
U+000C3
Ã
Congruent;
U+02261
≡
DoubleLongRightArrow;
U+027F9
⟹
U+0222F
∯
DoubleRightArrow;
U+021D2
⇒
∮
DoubleRightTee;
U+022A8
⊨
Atilde
U+000C3
Ã
Conint;
Auml;
U+000C4
Ä
ContourIntegral;
U+0222E
Auml
U+000C4
Ä
Copf;
U+02102
ℂ
DoubleUpArrow;
U+021D1
⇑
Backslash;
U+02216
∖
Coproduct;
U+02210
∐
DoubleUpDownArrow;
U+021D5
⇕
Barv;
U+02AE7
?
CounterClockwiseContourIntegral; U+02233
∳
DoubleVerticalBar;
U+02225
∥
Barwed;
U+02306
⌆
Cross;
U+02A2F
⨯
DownArrow;
U+02193
↓
Bcy;
U+00411
Б
Cscr;
U+1D49E
?
DownArrowBar;
U+02913
?
Because;
U+02235
∵
Cup;
U+022D3
?
DownArrowUpArrow;
U+021F5
⇵
Bernoullis;
U+0212C
ℬ
CupCap;
U+0224D
≍
DownBreve;
U+00311
◌̑
Beta;
U+00392
Β
DD;
U+02145
ⅅ
DownLeftRightVector;
U+02950
?
Bfr;
U+1D505
?
DDotrahd;
U+02911
?
DownLeftTeeVector;
U+0295E
?
Bopf;
U+1D539
𝔹
DJcy;
U+00402
Ђ
DownLeftVector;
U+021BD
↽
Breve;
U+002D8
˘
DScy;
U+00405
Ѕ
DownLeftVectorBar;
U+02956
?
Bscr;
U+0212C
ℬ
DZcy;
U+0040F
Џ
DownRightTeeVector;
U+0295F
?
Bumpeq;
U+0224E
≎
Dagger;
U+02021
‡
DownRightVector;
U+021C1
⇁
CHcy;
U+00427
Ч
Darr;
U+021A1
↡
DownRightVectorBar;
U+02957
?
COPY;
U+000A9
©
Dashv;
U+02AE4
?
DownTee;
U+022A4
⊤
COPY
U+000A9
©
Dcaron;
U+0010E
Ď
DownTeeArrow;
U+021A7
↧
627
Name
628
Character Glyph
Name
Character Glyph
Name
Character Glyph
Downarrow;
U+021D3
⇓
Itilde;
U+00128
Ĩ
Nfr;
U+1D511
?
Dscr;
U+1D49F
?
Iukcy;
U+00406
І
NoBreak;
U+02060
Dstrok;
U+00110
Đ
Iuml;
U+000CF
Ï
NonBreakingSpace;
U+000A0
ENG;
U+0014A
Ŋ
Iuml
U+000CF
Ï
Nopf;
U+02115
ETH;
U+000D0
Ð
Jcirc;
U+00134
Ĵ
Not;
U+02AEC
?
ETH
U+000D0
Ð
Jcy;
U+00419
Й
NotCongruent;
U+02262
≢
Eacute;
U+000C9
É
Jfr;
U+1D50D
?
NotCupCap;
U+0226D
≭
Eacute
U+000C9
É
Jopf;
U+1D541
𝕁
NotDoubleVerticalBar;
U+02226
∦
Ecaron;
U+0011A
Ě
Jscr;
U+1D4A5
?
NotElement;
U+02209
∉
Ecirc;
U+000CA
Ê
Jsercy;
U+00408
Ј
NotEqual;
U+02260
≠
Ecirc
U+000CA
Ê
Jukcy;
U+00404
Є
NotExists;
U+02204
∄
Ecy;
U+0042D
Э
KHcy;
U+00425
Х
NotGreater;
U+0226F
≯
Edot;
U+00116
Ė
KJcy;
U+0040C
Ќ
NotGreaterEqual;
U+02271
≱
Efr;
U+1D508
?
Kappa;
U+0039A
Κ
NotGreaterLess;
U+02279
≹
Egrave;
U+000C8
È
Kcedil;
U+00136
Ķ
NotGreaterTilde;
U+02275
≵
Egrave
U+000C8
È
Kcy;
U+0041A
К
NotLeftTriangle;
U+022EA
⋪
Element;
U+02208
∈
Kfr;
U+1D50E
?
NotLeftTriangleEqual;
U+022EC
⋬
Emacr;
U+00112
Ē
Kopf;
U+1D542
𝕂
NotLess;
U+0226E
≮
EmptySmallSquare;
U+025FB
◻
Kscr;
U+1D4A6
?
NotLessEqual;
U+02270
≰
EmptyVerySmallSquare;
U+025AB
▫
LJcy;
U+00409
Љ
NotLessGreater;
U+02278
≸
Eogon;
U+00118
Ę
LT;
U+0003C
<
NotLessTilde;
U+02274
≴
Eopf;
U+1D53C
𝔼
LT
U+0003C
<
NotPrecedes;
U+02280
Epsilon;
U+00395
Ε
Lacute;
U+00139
Ĺ
NotPrecedesSlantEqual;
U+022E0
⋠
Equal;
U+02A75
?
Lambda;
U+0039B
Λ
NotReverseElement;
U+0220C
∌
EqualTilde;
U+02242
≂
Lang;
U+027EA
⟪
NotRightTriangle;
U+022EB
⋫
Equilibrium;
U+021CC
⇌
Laplacetrf;
U+02112
ℒ
NotRightTriangleEqual;
U+022ED
⋭
Escr;
U+02130
ℰ
Larr;
U+0219E
↞
NotSquareSubsetEqual;
U+022E2
⋢
Esim;
U+02A73
?
Lcaron;
U+0013D
Ľ
NotSquareSupersetEqual;
U+022E3
⋣
Eta;
U+00397
Η
Lcedil;
U+0013B
Ļ
NotSubsetEqual;
U+02288
⊈
Euml;
U+000CB
Ë
Lcy;
U+0041B
Л
NotSucceeds;
U+02281
⊁
Euml
U+000CB
Ë
LeftAngleBracket;
U+027E8
?
NotSucceedsSlantEqual;
U+022E1
⋡
Exists;
U+02203
∃
LeftArrow;
U+02190
←
NotSupersetEqual;
U+02289
⊉
ExponentialE;
U+02147
ⅇ
LeftArrowBar;
U+021E4
⇤
NotTilde;
U+02241
≁
Fcy;
U+00424
Ф
LeftArrowRightArrow;
U+021C6
⇆
NotTildeEqual;
U+02244
≄
Ffr;
U+1D509
?
LeftCeiling;
U+02308
⌈
NotTildeFullEqual;
U+02247
≇
FilledSmallSquare;
U+025FC
◼
LeftDoubleBracket;
U+027E6
⟦
NotTildeTilde;
U+02249
≉
FilledVerySmallSquare;
U+025AA
▪
LeftDownTeeVector;
U+02961
?
NotVerticalBar;
U+02224
∤
Fopf;
U+1D53D
𝔽
LeftDownVector;
U+021C3
⇃
Nscr;
U+1D4A9
?
ForAll;
U+02200
∀
LeftDownVectorBar;
U+02959
?
Ntilde;
U+000D1
Ñ
Fouriertrf;
U+02131
ℱ
LeftFloor;
U+0230A
⌊
Ntilde
U+000D1
Fscr;
U+02131
ℱ
LeftRightArrow;
U+02194
↔
Nu;
U+0039D
Ν
GJcy;
U+00403
Ѓ
LeftRightVector;
U+0294E
?
OElig;
U+00152
Œ
GT;
U+0003E
>
LeftTee;
U+022A3
⊣
Oacute;
U+000D3
Ó
GT
U+0003E
>
LeftTeeArrow;
U+021A4
↤
Oacute
U+000D3
Ó
Gamma;
U+00393
Γ
LeftTeeVector;
U+0295A
?
Ocirc;
U+000D4
Ô
Gammad;
U+003DC
Ϝ
LeftTriangle;
U+022B2
⊲
Ocirc
U+000D4
Ô
Gbreve;
U+0011E
Ğ
LeftTriangleBar;
U+029CF
⧏
Ocy;
U+0041E
О
Gcedil;
U+00122
Ģ
LeftTriangleEqual;
U+022B4
⊴
Odblac;
U+00150
Ő
Gcirc;
U+0011C
Ĝ
LeftUpDownVector;
U+02951
?
Ofr;
U+1D512
?
Gcy;
U+00413
Г
LeftUpTeeVector;
U+02960
?
Ograve;
U+000D2
Ò
Gdot;
U+00120
Ġ
LeftUpVector;
U+021BF
↿
Ograve
U+000D2
Ò
Gfr;
U+1D50A
?
LeftUpVectorBar;
U+02958
?
Omacr;
U+0014C
Ō
Gg;
U+022D9
⋙
LeftVector;
U+021BC
↼
Omega;
U+003A9
Ω
Gopf;
U+1D53E
𝔾
LeftVectorBar;
U+02952
?
Omicron;
U+0039F
Ο
GreaterEqual;
U+02265
≥
Leftarrow;
U+021D0
⇐
Oopf;
U+1D546
𝕆
GreaterEqualLess;
U+022DB
⋛
Leftrightarrow;
U+021D4
⇔
OpenCurlyDoubleQuote;
U+0201C
“
GreaterFullEqual;
U+02267
≧
LessEqualGreater;
U+022DA
⋚
OpenCurlyQuote;
U+02018
‘
GreaterGreater;
U+02AA2
?
LessFullEqual;
U+02266
≦
Or;
U+02A54
?
GreaterLess;
U+02277
≷
LessGreater;
U+02276
≶
Oscr;
U+1D4AA
?
GreaterSlantEqual;
U+02A7E
⩾
LessLess;
U+02AA1
?
Oslash;
U+000D8
Ø
GreaterTilde;
U+02273
≳
LessSlantEqual;
U+02A7D
⩽
Oslash
U+000D8
Ø
Gscr;
U+1D4A2
?
LessTilde;
U+02272
≲
Otilde;
U+000D5
Õ
Gt;
U+0226B
≫
Lfr;
U+1D50F
?
Otilde
U+000D5
Õ
HARDcy;
U+0042A
Ъ
Ll;
U+022D8
⋘
Otimes;
U+02A37
?
Hacek;
U+002C7
ˇ
Lleftarrow;
U+021DA
⇚
Ouml;
U+000D6
Ö
Hat;
U+0005E
^
Lmidot;
U+0013F
Ŀ
Ouml
U+000D6
Ö
Hcirc;
U+00124
Ĥ
LongLeftArrow;
U+027F5
⟵
OverBar;
U+0203E
‾
Hfr;
U+0210C
ℌ
LongLeftRightArrow;
U+027F7
⟷
OverBrace;
U+023DE
?
HilbertSpace;
U+0210B
ℋ
LongRightArrow;
U+027F6
⟶
OverBracket;
U+023B4
?
Hopf;
U+0210D
ℍ
Longleftarrow;
U+027F8
⟸
OverParenthesis;
U+023DC
?
HorizontalLine;
U+02500
─
Longleftrightarrow;
U+027FA
⟺
PartialD;
U+02202
∂
Hscr;
U+0210B
ℋ
Longrightarrow;
U+027F9
⟹
Pcy;
U+0041F
П
Hstrok;
U+00126
Ħ
Lopf;
U+1D543
𝕃
Pfr;
U+1D513
?
HumpDownHump;
U+0224E
≎
LowerLeftArrow;
U+02199
↙
Phi;
U+003A6
Φ
HumpEqual;
U+0224F
≏
LowerRightArrow;
U+02198
↘
Pi;
U+003A0
Π
IEcy;
U+00415
Е
Lscr;
U+02112
ℒ
PlusMinus;
U+000B1
±
IJlig;
U+00132
IJ
Lsh;
U+021B0
↰
Poincareplane;
U+0210C
ℌ
IOcy;
U+00401
Ё
Lstrok;
U+00141
Ł
Popf;
U+02119
ℙ
Iacute;
U+000CD
Í
Lt;
U+0226A
≪
Pr;
U+02ABB
?
Iacute
U+000CD
Í
Map;
U+02905
?
Precedes;
U+0227A
≺
Icirc;
U+000CE
Î
Mcy;
U+0041C
М
PrecedesEqual;
U+02AAF
⪯
Icirc
U+000CE
Î
MediumSpace;
U+0205F
PrecedesSlantEqual;
U+0227C
≼
Icy;
U+00418
И
Mellintrf;
U+02133
ℳ
PrecedesTilde;
U+0227E
≾
Idot;
U+00130
p174
Mfr;
U+1D510
?
Prime;
U+02033
″
Ifr;
U+02111
ℑ
MinusPlus;
U+02213
∓
Product;
U+0220F
∏
Igrave;
U+000CC
Ì
Mopf;
U+1D544
𝕄
Proportion;
U+02237
∷
Igrave
U+000CC
Ì
Mscr;
U+02133
ℳ
Proportional;
U+0221D
∝
Im;
U+02111
ℑ
Mu;
U+0039C
Μ
Pscr;
U+1D4AB
?
Imacr;
U+0012A
Ī
NJcy;
U+0040A
Њ
Psi;
U+003A8
Ψ
ImaginaryI;
U+02148
ⅈ
Nacute;
U+00143
Ń
QUOT;
U+00022
"
Implies;
U+021D2
⇒
Ncaron;
U+00147
Ň
QUOT
U+00022
"
Int;
U+0222C
∬
Ncedil;
U+00145
Ņ
Qfr;
U+1D514
?
Integral;
U+0222B
∫
Ncy;
U+0041D
Н
Qopf;
U+0211A
ℚ
Intersection;
U+022C2
⋂
NegativeMediumSpace;
U+0200B
Qscr;
U+1D4AC
InvisibleComma;
U+02063
NegativeThickSpace;
U+0200B
RBarr;
U+02910
?
NegativeThinSpace;
U+0200B
REG;
U+000AE
®
REG
U+000AE
®
Ŕ
İ
ℕ
⊀
Ñ
?
InvisibleTimes;
U+02062
Iogon;
U+0012E
Į
NegativeVeryThinSpace;
U+0200B
Iopf;
U+1D540
𝕀
NestedGreaterGreater;
U+0226B
≫
Racute;
U+00154
Iota;
U+00399
Ι
NestedLessLess;
U+0226A
≪
Rang;
U+027EB
⟫
Iscr;
U+02110
ℐ
NewLine;
U+0000A
Rarr;
U+021A0
↠
Name
Character Glyph
Name
Character Glyph
Name
Character Glyph
Rarrtl;
U+02916
?
Tstrok;
U+00166
Ŧ
af;
U+02061
Rcaron;
U+00158
Ř
Uacute;
U+000DA
Ú
afr;
U+1D51E
?
Rcedil;
U+00156
Ŗ
Uacute
U+000DA
Ú
agrave;
U+000E0
à
Rcy;
U+00420
Р
Uarr;
U+0219F
↟
agrave
U+000E0
à
Re;
U+0211C
ℜ
Uarrocir;
U+02949
?
alefsym;
U+02135
ℵ
ReverseElement;
U+0220B
∋
Ubrcy;
U+0040E
Ў
aleph;
U+02135
ℵ
ReverseEquilibrium;
U+021CB
⇋
Ubreve;
U+0016C
Ŭ
alpha;
U+003B1
α
ReverseUpEquilibrium;
U+0296F
?
Ucirc;
U+000DB
Û
amacr;
U+00101
ā
Rfr;
U+0211C
ℜ
Ucirc
U+000DB
Û
amalg;
U+02A3F
?
Rho;
U+003A1
Ρ
Ucy;
U+00423
У
amp;
U+00026
&
RightAngleBracket;
U+027E9
?
Udblac;
U+00170
Ű
amp
U+00026
&
RightArrow;
U+02192
→
Ufr;
U+1D518
?
and;
U+02227
∧
RightArrowBar;
U+021E5
⇥
Ugrave;
U+000D9
Ù
andand;
U+02A55
?
RightArrowLeftArrow;
U+021C4
⇄
Ugrave
U+000D9
Ù
andd;
U+02A5C
?
RightCeiling;
U+02309
⌉
Umacr;
U+0016A
Ū
andslope;
U+02A58
?
RightDoubleBracket;
U+027E7
⟧
UnderBar;
U+0005F
_
andv;
U+02A5A
?
RightDownTeeVector;
U+0295D
?
UnderBrace;
U+023DF
?
ang;
U+02220
∠
RightDownVector;
U+021C2
⇂
UnderBracket;
U+023B5
?
ange;
U+029A4
?
RightDownVectorBar;
U+02955
?
UnderParenthesis;
U+023DD
?
angle;
U+02220
∠
RightFloor;
U+0230B
⌋
Union;
U+022C3
⋃
angmsd;
U+02221
∡
RightTee;
U+022A2
⊢
UnionPlus;
U+0228E
⊎
angmsdaa;
U+029A8
?
RightTeeArrow;
U+021A6
↦
Uogon;
U+00172
Ų
angmsdab;
U+029A9
?
RightTeeVector;
U+0295B
?
Uopf;
U+1D54C
𝕌
angmsdac;
U+029AA
?
RightTriangle;
U+022B3
⊳
UpArrow;
U+02191
↑
angmsdad;
U+029AB
?
RightTriangleBar;
U+029D0
⧐
UpArrowBar;
U+02912
?
angmsdae;
U+029AC
?
RightTriangleEqual;
U+022B5
⊵
UpArrowDownArrow;
U+021C5
⇅
angmsdaf;
U+029AD
?
RightUpDownVector;
U+0294F
?
UpDownArrow;
U+02195
↕
angmsdag;
U+029AE
?
RightUpTeeVector;
U+0295C
?
UpEquilibrium;
U+0296E
?
angmsdah;
U+029AF
?
RightUpVector;
U+021BE
↾
UpTee;
U+022A5
⊥
angrt;
U+0221F
∟
RightUpVectorBar;
U+02954
?
UpTeeArrow;
U+021A5
↥
angrtvb;
U+022BE
⊾
RightVector;
U+021C0
⇀
Uparrow;
U+021D1
⇑
angrtvbd;
U+0299D
?
RightVectorBar;
U+02953
?
Updownarrow;
U+021D5
⇕
angsph;
U+02222
∢
Rightarrow;
U+021D2
⇒
UpperLeftArrow;
U+02196
↖
angst;
U+000C5
Å
Ropf;
U+0211D
ℝ
UpperRightArrow;
U+02197
↗
angzarr;
U+0237C
?
RoundImplies;
U+02970
?
Upsi;
U+003D2
ϒ
aogon;
U+00105
ą
Rrightarrow;
U+021DB
⇛
Upsilon;
U+003A5
Υ
aopf;
U+1D552
𝕒
Rscr;
U+0211B
ℛ
Uring;
U+0016E
Ů
ap;
U+02248
≈
Rsh;
U+021B1
↱
Uscr;
U+1D4B0
?
apE;
U+02A70
?
RuleDelayed;
U+029F4
?
Utilde;
U+00168
Ũ
apacir;
U+02A6F
?
SHCHcy;
U+00429
Щ
Uuml;
U+000DC
Ü
ape;
U+0224A
≊
SHcy;
U+00428
Ш
Uuml
U+000DC
Ü
apid;
U+0224B
≋
SOFTcy;
U+0042C
Ь
VDash;
U+022AB
⊫
apos;
U+00027
'
Sacute;
U+0015A
Ś
Vbar;
U+02AEB
?
approx;
U+02248
≈
Sc;
U+02ABC
?
Vcy;
U+00412
В
approxeq;
U+0224A
≊
Scaron;
U+00160
Š
Vdash;
U+022A9
⊩
aring;
U+000E5
å
Scedil;
U+0015E
Ş
Vdashl;
U+02AE6
?
aring
U+000E5
å
Scirc;
U+0015C
Ŝ
Vee;
U+022C1
⋁
ascr;
U+1D4B6
?
Scy;
U+00421
С
Verbar;
U+02016
‖
ast;
U+0002A
*
Sfr;
U+1D516
?
Vert;
U+02016
‖
asymp;
U+02248
≈
ShortDownArrow;
U+02193
↓
VerticalBar;
U+02223
∣
asympeq;
U+0224D
≍
ShortLeftArrow;
U+02190
←
VerticalLine;
U+0007C
|
atilde;
U+000E3
ã
ShortRightArrow;
U+02192
→
VerticalSeparator;
U+02758
❘
atilde
U+000E3
ã
ShortUpArrow;
U+02191
↑
VerticalTilde;
U+02240
≀
auml;
U+000E4
ä
Sigma;
U+003A3
Σ
VeryThinSpace;
U+0200A
auml
U+000E4
ä
SmallCircle;
U+02218
∘
Vfr;
U+1D519
?
awconint;
U+02233
∳
Sopf;
U+1D54A
𝕊
Vopf;
U+1D54D
𝕍
awint;
U+02A11
⨑
Sqrt;
U+0221A
√
Vscr;
U+1D4B1
?
bNot;
U+02AED
?
Square;
U+025A1
□
Vvdash;
U+022AA
⊪
backcong;
U+0224C
≌
SquareIntersection;
U+02293
⊓
Wcirc;
U+00174
Ŵ
backepsilon;
U+003F6
SquareSubset;
U+0228F
⊏
Wedge;
U+022C0
⋀
backprime;
U+02035
‵
SquareSubsetEqual;
U+02291
⊑
Wfr;
U+1D51A
?
backsim;
U+0223D
∽
SquareSuperset;
U+02290
⊐
Wopf;
U+1D54E
𝕎
backsimeq;
U+022CD
⋍
SquareSupersetEqual;
U+02292
⊒
Wscr;
U+1D4B2
?
barvee;
U+022BD
⊽
SquareUnion;
U+02294
⊔
Xfr;
U+1D51B
?
barwed;
U+02305
⌅
Sscr;
U+1D4AE
?
Xi;
U+0039E
Ξ
barwedge;
U+02305
⌅
Star;
U+022C6
⋆
Xopf;
U+1D54F
𝕏
bbrk;
U+023B5
?
Sub;
U+022D0
?
Xscr;
U+1D4B3
?
bbrktbrk;
U+023B6
?
Subset;
U+022D0
?
YAcy;
U+0042F
Я
bcong;
U+0224C
≌
SubsetEqual;
U+02286
⊆
YIcy;
U+00407
Ї
bcy;
U+00431
б
Succeeds;
U+0227B
≻
YUcy;
U+0042E
Ю
bdquo;
U+0201E
„
SucceedsEqual;
U+02AB0
⪰
Yacute;
U+000DD
Ý
becaus;
U+02235
∵
SucceedsSlantEqual;
U+0227D
≽
Yacute
U+000DD
Ý
because;
U+02235
∵
SucceedsTilde;
U+0227F
≿
Ycirc;
U+00176
Ŷ
bemptyv;
U+029B0
?
SuchThat;
U+0220B
∋
Ycy;
U+0042B
Ы
bepsi;
U+003F6
϶
Sum;
U+02211
∑
Yfr;
U+1D51C
?
bernou;
U+0212C
ℬ
Sup;
U+022D1
?
Yopf;
U+1D550
𝕐
beta;
U+003B2
β
Superset;
U+02283
⊃
Yscr;
U+1D4B4
?
beth;
U+02136
ℶ
SupersetEqual;
U+02287
⊇
Yuml;
U+00178
Ÿ
between;
U+0226C
≬
Supset;
U+022D1
?
ZHcy;
U+00416
Ж
bfr;
U+1D51F
?
THORN;
U+000DE
Þ
Zacute;
U+00179
Ź
bigcap;
U+022C2
⋂
THORN
U+000DE
Þ
Zcaron;
U+0017D
Ž
bigcirc;
U+025EF
◯
TRADE;
U+02122
™
Zcy;
U+00417
З
bigcup;
U+022C3
⋃
TSHcy;
U+0040B
Ћ
Zdot;
U+0017B
Ż
bigodot;
U+02A00
⨀
TScy;
U+00426
Ц
ZeroWidthSpace;
U+0200B
Tab;
U+00009
Zeta;
U+00396
Tau;
U+003A4
Τ
Zfr;
Tcaron;
U+00164
Ť
Zopf;
Tcedil;
U+00162
Ţ
Tcy;
U+00422
Tfr;
U+1D517
Therefore;
϶
bigoplus;
U+02A01
⨁
Ζ
bigotimes;
U+02A02
⨂
U+02128
ℨ
bigsqcup;
U+02A06
?
U+02124
ℤ
bigstar;
U+02605
★
Zscr;
U+1D4B5
?
bigtriangledown;
U+025BD
▽
Т
aacute;
U+000E1
á
bigtriangleup;
U+025B3
△
?
aacute
U+000E1
á
biguplus;
U+02A04
?
U+02234
∴
abreve;
U+00103
ă
bigvee;
U+022C1
⋁
Theta;
U+00398
Θ
ac;
U+0223E
∾
bigwedge;
U+022C0
⋀
ThinSpace;
U+02009
acd;
U+0223F
∿
bkarow;
U+0290D
?
Tilde;
U+0223C
∼
acirc;
U+000E2
â
blacklozenge;
U+029EB
⧫
TildeEqual;
U+02243
≃
acirc
U+000E2
â
blacksquare;
U+025AA
▪
TildeFullEqual;
U+02245
≅
acute;
U+000B4
´
blacktriangle;
U+025B4
▴
TildeTilde;
U+02248
≈
acute
U+000B4
´
blacktriangledown;
U+025BE
▾
Topf;
U+1D54B
𝕋
acy;
U+00430
а
blacktriangleleft;
U+025C2
◂
TripleDot;
U+020DB
◌?
aelig;
U+000E6
æ
blacktriangleright;
U+025B8
▸
Tscr;
U+1D4AF
?
aelig
U+000E6
æ
blank;
U+02423
␣
629
Name
630
Character Glyph
Name
Character Glyph
Name
Character Glyph
blk12;
U+02592
▒
circ;
U+002C6
ˆ
divideontimes;
U+022C7
blk14;
U+02591
░
circeq;
U+02257
≗
divonx;
U+022C7
?
?
blk34;
U+02593
▓
circlearrowleft;
U+021BA
↺
djcy;
U+00452
ђ
block;
U+02588
█
circlearrowright;
U+021BB
↻
dlcorn;
U+0231E
⌞
bnot;
U+02310
⌐
circledR;
U+000AE
®
dlcrop;
U+0230D
⌍
bopf;
U+1D553
𝕓
circledS;
U+024C8
?
dollar;
U+00024
$
bot;
U+022A5
⊥
circledast;
U+0229B
⊛
dopf;
U+1D555
𝕕
bottom;
U+022A5
⊥
circledcirc;
U+0229A
⊚
dot;
U+002D9
˙
bowtie;
U+022C8
⋈
circleddash;
U+0229D
⊝
doteq;
U+02250
≐
boxDL;
U+02557
╗
cire;
U+02257
≗
doteqdot;
U+02251
≑
boxDR;
U+02554
╔
cirfnint;
U+02A10
⨐
dotminus;
U+02238
∸
boxDl;
U+02556
╖
cirmid;
U+02AEF
?
dotplus;
U+02214
∔
boxDr;
U+02553
╓
cirscir;
U+029C2
?
dotsquare;
U+022A1
⊡
boxH;
U+02550
═
clubs;
U+02663
♣
doublebarwedge;
U+02306
⌆
boxHD;
U+02566
╦
clubsuit;
U+02663
♣
downarrow;
U+02193
↓
boxHU;
U+02569
╩
colon;
U+0003A
:
downdownarrows;
U+021CA
⇊
boxHd;
U+02564
╤
colone;
U+02254
≔
downharpoonleft;
U+021C3
⇃
boxHu;
U+02567
╧
coloneq;
U+02254
≔
downharpoonright;
U+021C2
⇂
boxUL;
U+0255D
╝
comma;
U+0002C
,
drbkarow;
U+02910
?
boxUR;
U+0255A
╚
commat;
U+00040
@
drcorn;
U+0231F
⌟
boxUl;
U+0255C
╜
comp;
U+02201
∁
drcrop;
U+0230C
⌌
boxUr;
U+02559
╙
compfn;
U+02218
∘
dscr;
U+1D4B9
?
boxV;
U+02551
║
complement;
U+02201
∁
dscy;
U+00455
ѕ
boxVH;
U+0256C
╬
complexes;
U+02102
ℂ
dsol;
U+029F6
?
boxVL;
U+02563
╣
cong;
U+02245
≅
dstrok;
U+00111
đ
boxVR;
U+02560
╠
congdot;
U+02A6D
?
dtdot;
U+022F1
⋱
boxVh;
U+0256B
╫
conint;
U+0222E
∮
dtri;
U+025BF
▿
boxVl;
U+02562
╢
copf;
U+1D554
𝕔
dtrif;
U+025BE
▾
boxVr;
U+0255F
╟
coprod;
U+02210
∐
duarr;
U+021F5
⇵
boxbox;
U+029C9
?
copy;
U+000A9
©
duhar;
U+0296F
boxdL;
U+02555
╕
copy
U+000A9
©
dwangle;
U+029A6
?
boxdR;
U+02552
╒
copysr;
U+02117
℗
dzcy;
U+0045F
џ
boxdl;
U+02510
┐
crarr;
U+021B5
↵
dzigrarr;
U+027FF
⟿
boxdr;
U+0250C
┌
cross;
U+02717
✗
eDDot;
U+02A77
?
boxh;
U+02500
─
cscr;
U+1D4B8
?
eDot;
U+02251
≑
boxhD;
U+02565
╥
csub;
U+02ACF
?
eacute;
U+000E9
é
boxhU;
U+02568
╨
csube;
U+02AD1
?
eacute
U+000E9
é
boxhd;
U+0252C
┬
csup;
U+02AD0
?
easter;
U+02A6E
?
boxhu;
U+02534
┴
csupe;
U+02AD2
?
ecaron;
U+0011B
ě
boxminus;
U+0229F
⊟
ctdot;
U+022EF
⋯
ecir;
U+02256
≖
boxplus;
U+0229E
⊞
cudarrl;
U+02938
?
ecirc;
U+000EA
ê
boxtimes;
U+022A0
⊠
cudarrr;
U+02935
?
ecirc
U+000EA
ê
boxuL;
U+0255B
╛
cuepr;
U+022DE
⋞
ecolon;
U+02255
≕
boxuR;
U+02558
╘
cuesc;
U+022DF
⋟
ecy;
U+0044D
э
boxul;
U+02518
┘
cularr;
U+021B6
↶
edot;
U+00117
ė
boxur;
U+02514
└
cularrp;
U+0293D
?
ee;
U+02147
ⅇ
boxv;
U+02502
│
cup;
U+0222A
∪
efDot;
U+02252
≒
boxvH;
U+0256A
╪
cupbrcap;
U+02A48
?
efr;
U+1D522
?
boxvL;
U+02561
╡
cupcap;
U+02A46
?
eg;
U+02A9A
⪚
boxvR;
U+0255E
╞
cupcup;
U+02A4A
?
egrave;
U+000E8
boxvh;
U+0253C
┼
cupdot;
U+0228D
⊍
egrave
U+000E8
è
boxvl;
U+02524
┤
cupor;
U+02A45
?
egs;
U+02A96
⪖
boxvr;
U+0251C
├
curarr;
U+021B7
↷
egsdot;
U+02A98
⪘
bprime;
U+02035
‵
curarrm;
U+0293C
?
el;
U+02A99
⪙
breve;
U+002D8
˘
curlyeqprec;
U+022DE
⋞
elinters;
U+023E7
?
brvbar;
U+000A6
¦
curlyeqsucc;
U+022DF
⋟
ell;
U+02113
ℓ
brvbar
U+000A6
¦
curlyvee;
U+022CE
?
els;
U+02A95
⪕
bscr;
U+1D4B7
?
curlywedge;
U+022CF
?
elsdot;
U+02A97
bsemi;
U+0204F
⁏
curren;
U+000A4
¤
emacr;
U+00113
ē
bsim;
U+0223D
∽
curren
U+000A4
¤
empty;
U+02205
∅
bsime;
U+022CD
⋍
curvearrowleft;
U+021B6
↶
emptyset;
U+02205
∅
bsol;
U+0005C
\
curvearrowright;
U+021B7
↷
emptyv;
U+02205
∅
bsolb;
U+029C5
?
cuvee;
U+022CE
?
emsp13;
U+02004
bsolhsub;
U+027C8
?
cuwed;
U+022CF
?
emsp14;
U+02005
bull;
U+02022
•
cwconint;
U+02232
∲
emsp;
U+02003
bullet;
U+02022
•
cwint;
U+02231
∱
eng;
U+0014B
bump;
U+0224E
≎
cylcty;
U+0232D
?
ensp;
U+02002
bumpE;
U+02AAE
⪮
dArr;
U+021D3
⇓
eogon;
U+00119
ę
bumpe;
U+0224F
≏
dHar;
U+02965
?
eopf;
U+1D556
𝕖
bumpeq;
U+0224F
≏
dagger;
U+02020
†
epar;
U+022D5
?
cacute;
U+00107
ć
daleth;
U+02138
ℸ
eparsl;
U+029E3
?
cap;
U+02229
∩
darr;
U+02193
↓
eplus;
U+02A71
?
capand;
U+02A44
?
dash;
U+02010
‐
epsi;
U+003B5
ε
capbrcup;
U+02A49
?
dashv;
U+022A3
⊣
epsilon;
U+003B5
ε
capcap;
U+02A4B
?
dbkarow;
U+0290F
?
epsiv;
U+003F5
ϵ
capcup;
U+02A47
?
dblac;
U+002DD
˝
eqcirc;
U+02256
≖
capdot;
U+02A40
?
dcaron;
U+0010F
ď
eqcolon;
U+02255
≕
caret;
U+02041
⁁
dcy;
U+00434
д
eqsim;
U+02242
≂
caron;
U+002C7
ˇ
dd;
U+02146
ⅆ
eqslantgtr;
U+02A96
⪖
ccaps;
U+02A4D
?
ddagger;
U+02021
‡
eqslantless;
U+02A95
⪕
ccaron;
U+0010D
č
ddarr;
U+021CA
⇊
equals;
U+0003D
=
ccedil;
U+000E7
ç
ddotseq;
U+02A77
?
equest;
U+0225F
≟
ccedil
U+000E7
ç
deg;
U+000B0
°
equiv;
U+02261
≡
ccirc;
U+00109
ĉ
deg
U+000B0
°
equivDD;
U+02A78
?
ccups;
U+02A4C
?
delta;
U+003B4
δ
eqvparsl;
U+029E5
?
ccupssm;
U+02A50
?
demptyv;
U+029B1
?
erDot;
U+02253
≓
cdot;
U+0010B
ċ
dfisht;
U+0297F
?
erarr;
U+02971
?
cedil;
U+000B8
¸
dfr;
U+1D521
?
escr;
U+0212F
ℯ
cedil
U+000B8
¸
dharl;
U+021C3
⇃
esdot;
U+02250
≐
cemptyv;
U+029B2
?
dharr;
U+021C2
⇂
esim;
U+02242
≂
cent;
U+000A2
¢
diam;
U+022C4
⋄
eta;
U+003B7
η
cent
U+000A2
¢
diamond;
U+022C4
⋄
eth;
U+000F0
ð
centerdot;
U+000B7
·
diamondsuit;
U+02666
♦
eth
U+000F0
ð
cfr;
U+1D520
?
diams;
U+02666
♦
euml;
U+000EB
ë
chcy;
U+00447
ч
die;
U+000A8
¨
euml
U+000EB
ë
check;
U+02713
✓
digamma;
U+003DD
ϝ
euro;
U+020AC
€
checkmark;
U+02713
✓
disin;
U+022F2
⋲
excl;
U+00021
!
chi;
U+003C7
χ
div;
U+000F7
÷
exist;
U+02203
∃
cir;
U+025CB
○
divide;
U+000F7
÷
expectation;
U+02130
ℰ
cirE;
U+029C3
?
divide
U+000F7
÷
exponentiale;
U+02147
ⅇ
?
è
⪗
ŋ
Name
Character Glyph
Name
Character Glyph
Name
Character Glyph
fallingdotseq;
U+02252
≒
harr;
U+02194
↔
lBarr;
U+0290E
?
fcy;
U+00444
ф
harrcir;
U+02948
?
lE;
U+02266
≦
female;
U+02640
♀
harrw;
U+021AD
↭
lEg;
U+02A8B
⪋
ffilig;
U+0FB03
ffi
hbar;
U+0210F
ℏ
lHar;
U+02962
?
fflig;
U+0FB00
ff
hcirc;
U+00125
ĥ
lacute;
U+0013A
ĺ
ffllig;
U+0FB04
ffl
hearts;
U+02665
♥
laemptyv;
U+029B4
?
ffr;
U+1D523
?
heartsuit;
U+02665
♥
lagran;
U+02112
ℒ
filig;
U+0FB01
fi
hellip;
U+02026
…
lambda;
U+003BB
λ
flat;
U+0266D
♭
hercon;
U+022B9
⊹
lang;
U+027E8
?
fllig;
U+0FB02
fl
hfr;
U+1D525
?
langd;
U+02991
?
fltns;
U+025B1
▱
hksearow;
U+02925
?
langle;
U+027E8
?
fnof;
U+00192
ƒ
hkswarow;
U+02926
?
lap;
U+02A85
⪅
fopf;
U+1D557
𝕗
hoarr;
U+021FF
⇿
laquo;
U+000AB
forall;
U+02200
∀
homtht;
U+0223B
∻
laquo
U+000AB
«
fork;
U+022D4
?
hookleftarrow;
U+021A9
↩
larr;
U+02190
←
forkv;
U+02AD9
?
hookrightarrow;
U+021AA
↪
larrb;
U+021E4
⇤
fpartint;
U+02A0D
⨍
hopf;
U+1D559
𝕙
larrbfs;
U+0291F
?
frac12;
U+000BD
½
horbar;
U+02015
―
larrfs;
U+0291D
?
frac12
U+000BD
½
hscr;
U+1D4BD
?
larrhk;
U+021A9
↩
frac13;
U+02153
⅓
hslash;
U+0210F
ℏ
larrlp;
U+021AB
↫
frac14;
U+000BC
¼
hstrok;
U+00127
ħ
larrpl;
U+02939
frac14
U+000BC
¼
hybull;
U+02043
⁃
larrsim;
U+02973
?
frac15;
U+02155
⅕
hyphen;
U+02010
‐
larrtl;
U+021A2
↢
frac16;
U+02159
⅙
iacute;
U+000ED
í
lat;
U+02AAB
?
frac18;
U+0215B
⅛
iacute
U+000ED
í
latail;
U+02919
?
frac23;
U+02154
⅔
ic;
U+02063
late;
U+02AAD
?
frac25;
U+02156
⅖
icirc;
U+000EE
î
lbarr;
U+0290C
?
frac34;
U+000BE
¾
icirc
U+000EE
î
lbbrk;
U+02772
❲
frac34
U+000BE
¾
icy;
U+00438
и
lbrace;
U+0007B
{
frac35;
U+02157
⅗
iecy;
U+00435
е
lbrack;
U+0005B
[
frac38;
U+0215C
⅜
iexcl;
U+000A1
¡
lbrke;
U+0298B
?
frac45;
U+02158
⅘
iexcl
U+000A1
¡
lbrksld;
U+0298F
?
frac56;
U+0215A
⅚
iff;
U+021D4
⇔
lbrkslu;
U+0298D
?
frac58;
U+0215D
⅝
ifr;
U+1D526
?
lcaron;
U+0013E
ľ
frac78;
U+0215E
⅞
igrave;
U+000EC
ì
lcedil;
U+0013C
ļ
frasl;
U+02044
⁄
igrave
U+000EC
ì
lceil;
U+02308
⌈
frown;
U+02322
?
ii;
U+02148
ⅈ
lcub;
U+0007B
{
fscr;
U+1D4BB
?
iiiint;
U+02A0C
⨌
lcy;
U+0043B
л
gE;
U+02267
≧
iiint;
U+0222D
∭
ldca;
U+02936
?
gEl;
U+02A8C
⪌
iinfin;
U+029DC
?
ldquo;
U+0201C
gacute;
U+001F5
ǵ
iiota;
U+02129
℩
ldquor;
U+0201E
„
gamma;
U+003B3
γ
ijlig;
U+00133
ij
ldrdhar;
U+02967
?
gammad;
U+003DD
ϝ
imacr;
U+0012B
ī
ldrushar;
U+0294B
?
gap;
U+02A86
⪆
image;
U+02111
ℑ
ldsh;
U+021B2
↲
gbreve;
U+0011F
ğ
imagline;
U+02110
ℐ
le;
U+02264
≤
gcirc;
U+0011D
ĝ
imagpart;
U+02111
ℑ
leftarrow;
U+02190
←
gcy;
U+00433
г
imath;
U+00131
ı
leftarrowtail;
U+021A2
↢
gdot;
U+00121
ġ
imof;
U+022B7
⊷
leftharpoondown;
U+021BD
↽
ge;
U+02265
≥
imped;
U+001B5
Ƶ
leftharpoonup;
U+021BC
↼
gel;
U+022DB
⋛
in;
U+02208
∈
leftleftarrows;
U+021C7
⇇
geq;
U+02265
≥
incare;
U+02105
℅
leftrightarrow;
U+02194
↔
geqq;
U+02267
≧
infin;
U+0221E
∞
leftrightarrows;
U+021C6
⇆
geqslant;
U+02A7E
⩾
infintie;
U+029DD
?
leftrightharpoons;
U+021CB
⇋
ges;
U+02A7E
⩾
inodot;
U+00131
ı
leftrightsquigarrow;
U+021AD
↭
gescc;
U+02AA9
?
int;
U+0222B
∫
leftthreetimes;
U+022CB
⋋
gesdot;
U+02A80
⪀
intcal;
U+022BA
⊺
leg;
U+022DA
⋚
gesdoto;
U+02A82
⪂
integers;
U+02124
ℤ
leq;
U+02264
≤
gesdotol;
U+02A84
⪄
intercal;
U+022BA
⊺
leqq;
U+02266
≦
gesles;
U+02A94
⪔
intlarhk;
U+02A17
⨗
leqslant;
U+02A7D
⩽
gfr;
U+1D524
?
intprod;
U+02A3C
?
les;
U+02A7D
⩽
gg;
U+0226B
≫
iocy;
U+00451
ё
lescc;
U+02AA8
?
ggg;
U+022D9
⋙
iogon;
U+0012F
į
lesdot;
U+02A7F
⩿
gimel;
U+02137
ℷ
iopf;
U+1D55A
𝕚
lesdoto;
U+02A81
⪁
gjcy;
U+00453
ѓ
iota;
U+003B9
ι
lesdotor;
U+02A83
⪃
gl;
U+02277
≷
iprod;
U+02A3C
?
lesges;
U+02A93
⪓
glE;
U+02A92
⪒
iquest;
U+000BF
¿
lessapprox;
U+02A85
⪅
gla;
U+02AA5
?
iquest
U+000BF
¿
lessdot;
U+022D6
⋖
glj;
U+02AA4
?
iscr;
U+1D4BE
?
lesseqgtr;
U+022DA
⋚
gnE;
U+02269
≩
isin;
U+02208
∈
lesseqqgtr;
U+02A8B
⪋
gnap;
U+02A8A
⪊
isinE;
U+022F9
⋹
lessgtr;
U+02276
≶
gnapprox;
U+02A8A
⪊
isindot;
U+022F5
⋵
lesssim;
U+02272
≲
gne;
U+02A88
⪈
isins;
U+022F4
⋴
lfisht;
U+0297C
?
gneq;
U+02A88
⪈
isinsv;
U+022F3
⋳
lfloor;
U+0230A
⌊
gneqq;
U+02269
≩
isinv;
U+02208
∈
lfr;
U+1D529
?
gnsim;
U+022E7
⋧
it;
U+02062
lg;
U+02276
≶
gopf;
U+1D558
𝕘
itilde;
U+00129
ĩ
lgE;
U+02A91
⪑
grave;
U+00060
`
iukcy;
U+00456
і
lhard;
U+021BD
↽
gscr;
U+0210A
g
iuml;
U+000EF
ï
lharu;
U+021BC
↼
gsim;
U+02273
≳
iuml
U+000EF
ï
lharul;
U+0296A
?
gsime;
U+02A8E
⪎
jcirc;
U+00135
ĵ
lhblk;
U+02584
▄
gsiml;
U+02A90
⪐
jcy;
U+00439
й
ljcy;
U+00459
љ
gt;
U+0003E
>
jfr;
U+1D527
?
ll;
U+0226A
≪
gt
U+0003E
>
jmath;
U+00237
ȷ
llarr;
U+021C7
⇇
gtcc;
U+02AA7
?
jopf;
U+1D55B
𝕛
llcorner;
U+0231E
⌞
gtcir;
U+02A7A
?
jscr;
U+1D4BF
?
llhard;
U+0296B
?
gtdot;
U+022D7
⋗
jsercy;
U+00458
ј
lltri;
U+025FA
◺
gtlPar;
U+02995
?
jukcy;
U+00454
є
lmidot;
U+00140
ŀ
gtquest;
U+02A7C
?
kappa;
U+003BA
κ
lmoust;
U+023B0
?
gtrapprox;
U+02A86
⪆
kappav;
U+003F0
ϰ
lmoustache;
U+023B0
?
gtrarr;
U+02978
?
kcedil;
U+00137
ķ
lnE;
U+02268
≨
gtrdot;
U+022D7
⋗
kcy;
U+0043A
к
lnap;
U+02A89
⪉
gtreqless;
U+022DB
⋛
kfr;
U+1D528
?
lnapprox;
U+02A89
⪉
gtreqqless;
U+02A8C
⪌
kgreen;
U+00138
ĸ
lne;
U+02A87
⪇
gtrless;
U+02277
≷
khcy;
U+00445
х
lneq;
U+02A87
⪇
gtrsim;
U+02273
≳
kjcy;
U+0045C
ќ
lneqq;
U+02268
≨
hArr;
U+021D4
⇔
kopf;
U+1D55C
𝕜
lnsim;
U+022E6
⋦
hairsp;
U+0200A
kscr;
U+1D4C0
?
loang;
U+027EC
?
half;
U+000BD
½
lAarr;
U+021DA
⇚
loarr;
U+021FD
⇽
hamilt;
U+0210B
ℋ
lArr;
U+021D0
⇐
lobrk;
U+027E6
⟦
hardcy;
U+0044A
ъ
lAtail;
U+0291B
?
longleftarrow;
U+027F5
⟵
«
?
“
631
Name
632
Character Glyph
Name
Character Glyph
Name
Character Glyph
longleftrightarrow;
U+027F7
⟷
nbsp;
U+000A0
nvdash;
U+022AC
⊬
longmapsto;
U+027FC
⟼
nbsp
U+000A0
nvinfin;
U+029DE
?
longrightarrow;
U+027F6
⟶
ncap;
U+02A43
?
nvlArr;
U+02902
looparrowleft;
U+021AB
↫
ncaron;
U+00148
ň
nvrArr;
U+02903
?
looparrowright;
U+021AC
↬
ncedil;
U+00146
ņ
nwArr;
U+021D6
⇖
lopar;
U+02985
?
ncong;
U+02247
≇
nwarhk;
U+02923
?
lopf;
U+1D55D
𝕝
ncup;
U+02A42
?
nwarr;
U+02196
↖
loplus;
U+02A2D
?
ncy;
U+0043D
н
nwarrow;
U+02196
↖
lotimes;
U+02A34
?
ndash;
U+02013
–
nwnear;
U+02927
?
lowast;
U+02217
∗
ne;
U+02260
≠
oS;
U+024C8
?
lowbar;
U+0005F
_
neArr;
U+021D7
⇗
oacute;
U+000F3
ó
loz;
U+025CA
◊
nearhk;
U+02924
?
oacute
U+000F3
ó
lozenge;
U+025CA
◊
nearr;
U+02197
↗
oast;
U+0229B
⊛
lozf;
U+029EB
⧫
nearrow;
U+02197
↗
ocir;
U+0229A
⊚
lpar;
U+00028
(
nequiv;
U+02262
≢
ocirc;
U+000F4
ô
lparlt;
U+02993
?
nesear;
U+02928
?
ocirc
U+000F4
ô
lrarr;
U+021C6
⇆
nexist;
U+02204
∄
ocy;
U+0043E
о
lrcorner;
U+0231F
⌟
nexists;
U+02204
∄
odash;
U+0229D
⊝
lrhar;
U+021CB
⇋
nfr;
U+1D52B
?
odblac;
U+00151
ő
lrhard;
U+0296D
?
nge;
U+02271
≱
odiv;
U+02A38
?
lrm;
U+0200E
ngeq;
U+02271
≱
odot;
U+02299
⊙
lrtri;
U+022BF
⊿
ngsim;
U+02275
≵
odsold;
U+029BC
?
lsaquo;
U+02039
‹
ngt;
U+0226F
≯
oelig;
U+00153
œ
lscr;
U+1D4C1
?
ngtr;
U+0226F
≯
ofcir;
U+029BF
?
lsh;
U+021B0
↰
nhArr;
U+021CE
⇎
ofr;
U+1D52C
?
lsim;
U+02272
≲
nharr;
U+021AE
↮
ogon;
U+002DB
˛
lsime;
U+02A8D
⪍
nhpar;
U+02AF2
?
ograve;
U+000F2
ò
lsimg;
U+02A8F
⪏
ni;
U+0220B
∋
ograve
U+000F2
ò
lsqb;
U+0005B
[
nis;
U+022FC
⋼
ogt;
U+029C1
?
lsquo;
U+02018
‘
nisd;
U+022FA
⋺
ohbar;
U+029B5
?
lsquor;
U+0201A
‚
niv;
U+0220B
∋
ohm;
U+003A9
Ω
lstrok;
U+00142
ł
njcy;
U+0045A
њ
oint;
U+0222E
∮
lt;
U+0003C
<
nlArr;
U+021CD
⇍
olarr;
U+021BA
↺
lt
U+0003C
<
nlarr;
U+0219A
↚
olcir;
U+029BE
?
ltcc;
U+02AA6
?
nldr;
U+02025
‥
olcross;
U+029BB
?
ltcir;
U+02A79
?
nle;
U+02270
≰
oline;
U+0203E
‾
ltdot;
U+022D6
⋖
nleftarrow;
U+0219A
↚
olt;
U+029C0
?
lthree;
U+022CB
⋋
nleftrightarrow;
U+021AE
↮
omacr;
U+0014D
ō
ltimes;
U+022C9
⋉
nleq;
U+02270
≰
omega;
U+003C9
ω
ltlarr;
U+02976
?
nless;
U+0226E
≮
omicron;
U+003BF
ltquest;
U+02A7B
?
nlsim;
U+02274
≴
omid;
U+029B6
?
ltrPar;
U+02996
?
nlt;
U+0226E
≮
ominus;
U+02296
⊖
ltri;
U+025C3
◃
nltri;
U+022EA
⋪
oopf;
U+1D560
𝕠
ltrie;
U+022B4
⊴
nltrie;
U+022EC
⋬
opar;
U+029B7
?
ltrif;
U+025C2
◂
nmid;
U+02224
∤
operp;
U+029B9
?
lurdshar;
U+0294A
?
nopf;
U+1D55F
𝕟
oplus;
U+02295
⊕
luruhar;
U+02966
?
not;
U+000AC
¬
or;
U+02228
∨
mDDot;
U+0223A
∺
not
U+000AC
¬
orarr;
U+021BB
↻
macr;
U+000AF
¯
notin;
U+02209
∉
ord;
U+02A5D
?
macr
U+000AF
¯
notinva;
U+02209
∉
order;
U+02134
male;
U+02642
♂
notinvb;
U+022F7
⋷
orderof;
U+02134
ℴ
malt;
U+02720
✠
notinvc;
U+022F6
⋶
ordf;
U+000AA
ª
maltese;
U+02720
✠
notni;
U+0220C
∌
ordf
U+000AA
ª
map;
U+021A6
↦
notniva;
U+0220C
∌
ordm;
U+000BA
º
mapsto;
U+021A6
↦
notnivb;
U+022FE
⋾
ordm
U+000BA
º
mapstodown;
U+021A7
↧
notnivc;
U+022FD
⋽
origof;
U+022B6
⊶
mapstoleft;
U+021A4
↤
npar;
U+02226
∦
oror;
U+02A56
?
mapstoup;
U+021A5
↥
nparallel;
U+02226
∦
orslope;
U+02A57
?
marker;
U+025AE
▮
npolint;
U+02A14
⨔
orv;
U+02A5B
mcomma;
U+02A29
?
npr;
U+02280
⊀
oscr;
U+02134
ℴ
mcy;
U+0043C
м
nprcue;
U+022E0
⋠
oslash;
U+000F8
ø
mdash;
U+02014
—
nprec;
U+02280
⊀
oslash
U+000F8
ø
measuredangle;
U+02221
∡
nrArr;
U+021CF
⇏
osol;
U+02298
⊘
mfr;
U+1D52A
?
nrarr;
U+0219B
↛
otilde;
U+000F5
õ
mho;
U+02127
℧
nrightarrow;
U+0219B
↛
otilde
U+000F5
õ
micro;
U+000B5
µ
nrtri;
U+022EB
⋫
otimes;
U+02297
⊗
micro
U+000B5
µ
nrtrie;
U+022ED
⋭
otimesas;
U+02A36
?
mid;
U+02223
∣
nsc;
U+02281
⊁
ouml;
U+000F6
ö
midast;
U+0002A
*
nsccue;
U+022E1
⋡
ouml
U+000F6
ö
midcir;
U+02AF0
?
nscr;
U+1D4C3
?
ovbar;
U+0233D
?
middot;
U+000B7
·
nshortmid;
U+02224
∤
par;
U+02225
∥
middot
U+000B7
·
nshortparallel;
U+02226
∦
para;
U+000B6
¶
minus;
U+02212
−
nsim;
U+02241
≁
para
U+000B6
¶
minusb;
U+0229F
⊟
nsime;
U+02244
≄
parallel;
U+02225
∥
minusd;
U+02238
∸
nsimeq;
U+02244
≄
parsim;
U+02AF3
?
minusdu;
U+02A2A
?
nsmid;
U+02224
∤
parsl;
U+02AFD
mlcp;
U+02ADB
?
nspar;
U+02226
∦
part;
U+02202
∂
mldr;
U+02026
…
nsqsube;
U+022E2
⋢
pcy;
U+0043F
п
mnplus;
U+02213
∓
nsqsupe;
U+022E3
⋣
percnt;
U+00025
%
models;
U+022A7
⊧
nsub;
U+02284
⊄
period;
U+0002E
.
mopf;
U+1D55E
𝕞
nsube;
U+02288
⊈
permil;
U+02030
‰
mp;
U+02213
∓
nsubseteq;
U+02288
⊈
perp;
U+022A5
⊥
mscr;
U+1D4C2
?
nsucc;
U+02281
⊁
pertenk;
U+02031
‱
mstpos;
U+0223E
∾
nsup;
U+02285
⊅
pfr;
U+1D52D
?
mu;
U+003BC
μ
nsupe;
U+02289
⊉
phi;
U+003C6
φ
multimap;
U+022B8
⊸
nsupseteq;
U+02289
⊉
phiv;
U+003D5
mumap;
U+022B8
⊸
ntgl;
U+02279
≹
phmmat;
U+02133
ℳ
nLeftarrow;
U+021CD
⇍
ntilde;
U+000F1
ñ
phone;
U+0260E
☎
nLeftrightarrow;
U+021CE
⇎
ntilde
U+000F1
ñ
pi;
U+003C0
π
nRightarrow;
U+021CF
⇏
ntlg;
U+02278
≸
pitchfork;
U+022D4
?
nVDash;
U+022AF
⊯
ntriangleleft;
U+022EA
⋪
piv;
U+003D6
ϖ
nVdash;
U+022AE
⊮
ntrianglelefteq;
U+022EC
⋬
planck;
U+0210F
ℏ
nabla;
U+02207
∇
ntriangleright;
U+022EB
⋫
planckh;
U+0210E
ℎ
nacute;
U+00144
ń
ntrianglerighteq;
U+022ED
⋭
plankv;
U+0210F
ℏ
nap;
U+02249
≉
nu;
U+003BD
ν
plus;
U+0002B
+
napos;
U+00149
ʼn
num;
U+00023
#
plusacir;
U+02A23
?
napprox;
U+02249
≉
numero;
U+02116
№
plusb;
U+0229E
⊞
natur;
U+0266E
♮
numsp;
U+02007
pluscir;
U+02A22
?
natural;
U+0266E
♮
nvDash;
U+022AD
⊭
plusdo;
U+02214
∔
naturals;
U+02115
ℕ
nvHarr;
U+02904
?
plusdu;
U+02A25
?
?
ο
ℴ
?
?
ϕ
Name
Character Glyph
Name
Character Glyph
Name
Character Glyph
pluse;
U+02A72
?
rect;
U+025AD
▭
simgE;
U+02AA0
⪠
plusmn;
U+000B1
±
reg;
U+000AE
®
siml;
U+02A9D
⪝
plusmn
U+000B1
±
reg
U+000AE
®
simlE;
U+02A9F
⪟
plussim;
U+02A26
?
rfisht;
U+0297D
?
simne;
U+02246
≆
plustwo;
U+02A27
?
rfloor;
U+0230B
⌋
simplus;
U+02A24
?
pm;
U+000B1
±
rfr;
U+1D52F
?
simrarr;
U+02972
?
pointint;
U+02A15
⨕
rhard;
U+021C1
⇁
slarr;
U+02190
←
popf;
U+1D561
𝕡
rharu;
U+021C0
⇀
smallsetminus;
U+02216
∖
pound;
U+000A3
£
rharul;
U+0296C
?
smashp;
U+02A33
?
pound
U+000A3
£
rho;
U+003C1
ρ
smeparsl;
U+029E4
?
pr;
U+0227A
≺
rhov;
U+003F1
ϱ
smid;
U+02223
∣
prE;
U+02AB3
⪳
rightarrow;
U+02192
→
smile;
U+02323
?
prap;
U+02AB7
⪷
rightarrowtail;
U+021A3
↣
smt;
U+02AAA
prcue;
U+0227C
≼
rightharpoondown;
U+021C1
⇁
smte;
U+02AAC
?
pre;
U+02AAF
⪯
rightharpoonup;
U+021C0
⇀
softcy;
U+0044C
ь
prec;
U+0227A
≺
rightleftarrows;
U+021C4
⇄
sol;
U+0002F
/
precapprox;
U+02AB7
⪷
rightleftharpoons;
U+021CC
⇌
solb;
U+029C4
?
preccurlyeq;
U+0227C
≼
rightrightarrows;
U+021C9
⇉
solbar;
U+0233F
?
preceq;
U+02AAF
⪯
rightsquigarrow;
U+0219D
↝
sopf;
U+1D564
𝕤
precnapprox;
U+02AB9
⪹
rightthreetimes;
U+022CC
⋌
spades;
U+02660
♠
precneqq;
U+02AB5
⪵
ring;
U+002DA
˚
spadesuit;
U+02660
♠
precnsim;
U+022E8
⋨
risingdotseq;
U+02253
≓
spar;
U+02225
∥
precsim;
U+0227E
≾
rlarr;
U+021C4
⇄
sqcap;
U+02293
⊓
prime;
U+02032
′
rlhar;
U+021CC
⇌
sqcup;
U+02294
⊔
primes;
U+02119
ℙ
rlm;
U+0200F
sqsub;
U+0228F
⊏
prnE;
U+02AB5
⪵
rmoust;
U+023B1
?
sqsube;
U+02291
⊑
prnap;
U+02AB9
⪹
rmoustache;
U+023B1
?
sqsubset;
U+0228F
⊏
prnsim;
U+022E8
⋨
rnmid;
U+02AEE
?
sqsubseteq;
U+02291
⊑
prod;
U+0220F
∏
roang;
U+027ED
?
sqsup;
U+02290
⊐
profalar;
U+0232E
?
roarr;
U+021FE
⇾
sqsupe;
U+02292
⊒
profline;
U+02312
⌒
robrk;
U+027E7
⟧
sqsupset;
U+02290
U+02986
?
sqsupseteq;
U+02292
⊒
?
⊐
profsurf;
U+02313
?
ropar;
prop;
U+0221D
∝
ropf;
U+1D563
𝕣
squ;
U+025A1
□
propto;
U+0221D
∝
roplus;
U+02A2E
?
square;
U+025A1
□
prsim;
U+0227E
≾
rotimes;
U+02A35
?
squarf;
U+025AA
▪
prurel;
U+022B0
?
rpar;
U+00029
)
squf;
U+025AA
▪
pscr;
U+1D4C5
?
rpargt;
U+02994
?
srarr;
U+02192
→
psi;
U+003C8
ψ
rppolint;
U+02A12
⨒
sscr;
U+1D4C8
?
puncsp;
U+02008
rrarr;
U+021C9
⇉
ssetmn;
U+02216
∖
qfr;
U+1D52E
?
rsaquo;
U+0203A
›
ssmile;
U+02323
qint;
U+02A0C
⨌
rscr;
U+1D4C7
?
sstarf;
U+022C6
⋆
qopf;
U+1D562
𝕢
rsh;
U+021B1
↱
star;
U+02606
☆
qprime;
U+02057
⁗
rsqb;
U+0005D
]
starf;
U+02605
★
qscr;
U+1D4C6
?
rsquo;
U+02019
’
straightepsilon;
U+003F5
ϵ
quaternions;
U+0210D
ℍ
rsquor;
U+02019
’
straightphi;
U+003D5
ϕ
quatint;
U+02A16
⨖
rthree;
U+022CC
⋌
strns;
U+000AF
¯
quest;
U+0003F
?
rtimes;
U+022CA
⋊
sub;
U+02282
⊂
questeq;
U+0225F
≟
rtri;
U+025B9
▹
subE;
U+02AC5
?
quot;
U+00022
"
rtrie;
U+022B5
⊵
subdot;
U+02ABD
?
quot
U+00022
"
rtrif;
U+025B8
▸
sube;
U+02286
⊆
rAarr;
U+021DB
⇛
rtriltri;
U+029CE
⧎
subedot;
U+02AC3
?
rArr;
U+021D2
⇒
ruluhar;
U+02968
?
submult;
U+02AC1
?
rAtail;
U+0291C
?
rx;
U+0211E
℞
subnE;
U+02ACB
?
rBarr;
U+0290F
?
sacute;
U+0015B
ś
subne;
U+0228A
⊊
rHar;
U+02964
?
sbquo;
U+0201A
‚
subplus;
U+02ABF
?
racute;
U+00155
ŕ
sc;
U+0227B
≻
subrarr;
U+02979
?
radic;
U+0221A
√
scE;
U+02AB4
⪴
subset;
U+02282
⊂
raemptyv;
U+029B3
?
scap;
U+02AB8
⪸
subseteq;
U+02286
⊆
rang;
U+027E9
?
scaron;
U+00161
š
subseteqq;
U+02AC5
?
rangd;
U+02992
?
sccue;
U+0227D
≽
subsetneq;
U+0228A
⊊
range;
U+029A5
?
sce;
U+02AB0
⪰
subsetneqq;
U+02ACB
?
rangle;
U+027E9
?
scedil;
U+0015F
ş
subsim;
U+02AC7
?
raquo;
U+000BB
»
scirc;
U+0015D
ŝ
subsub;
U+02AD5
?
raquo
U+000BB
»
scnE;
U+02AB6
⪶
subsup;
U+02AD3
?
rarr;
U+02192
→
scnap;
U+02ABA
⪺
succ;
U+0227B
≻
rarrap;
U+02975
?
scnsim;
U+022E9
⋩
succapprox;
U+02AB8
⪸
rarrb;
U+021E5
⇥
scpolint;
U+02A13
⨓
succcurlyeq;
U+0227D
≽
rarrbfs;
U+02920
?
scsim;
U+0227F
≿
succeq;
U+02AB0
⪰
rarrc;
U+02933
?
scy;
U+00441
с
succnapprox;
U+02ABA
⪺
rarrfs;
U+0291E
?
sdot;
U+022C5
⋅
succneqq;
U+02AB6
⪶
rarrhk;
U+021AA
↪
sdotb;
U+022A1
⊡
succnsim;
U+022E9
⋩
rarrlp;
U+021AC
↬
sdote;
U+02A66
?
succsim;
U+0227F
≿
rarrpl;
U+02945
?
seArr;
U+021D8
⇘
sum;
U+02211
∑
rarrsim;
U+02974
?
searhk;
U+02925
?
sung;
U+0266A
♪
rarrtl;
U+021A3
↣
searr;
U+02198
↘
sup1;
U+000B9
¹
rarrw;
U+0219D
↝
searrow;
U+02198
↘
sup1
U+000B9
¹
ratail;
U+0291A
?
sect;
U+000A7
§
sup2;
U+000B2
²
ratio;
U+02236
∶
sect
U+000A7
§
sup2
U+000B2
²
rationals;
U+0211A
ℚ
semi;
U+0003B
;
sup3;
U+000B3
³
rbarr;
U+0290D
?
seswar;
U+02929
?
sup3
U+000B3
³
rbbrk;
U+02773
❳
setminus;
U+02216
∖
sup;
U+02283
⊃
rbrace;
U+0007D
}
setmn;
U+02216
∖
supE;
U+02AC6
?
rbrack;
U+0005D
]
sext;
U+02736
✶
supdot;
U+02ABE
?
rbrke;
U+0298C
?
sfr;
U+1D530
?
supdsub;
U+02AD8
?
rbrksld;
U+0298E
?
sfrown;
U+02322
?
supe;
U+02287
⊇
rbrkslu;
U+02990
?
sharp;
U+0266F
♯
supedot;
U+02AC4
?
rcaron;
U+00159
ř
shchcy;
U+00449
щ
suphsol;
U+027C9
?
rcedil;
U+00157
ŗ
shcy;
U+00448
ш
suphsub;
U+02AD7
?
rceil;
U+02309
⌉
shortmid;
U+02223
∣
suplarr;
U+0297B
?
rcub;
U+0007D
}
shortparallel;
U+02225
∥
supmult;
U+02AC2
?
rcy;
U+00440
р
shy;
U+000AD
supnE;
U+02ACC
?
rdca;
U+02937
?
shy
U+000AD
supne;
U+0228B
⊋
rdldhar;
U+02969
?
sigma;
U+003C3
σ
supplus;
U+02AC0
?
rdquo;
U+0201D
”
sigmaf;
U+003C2
ς
supset;
U+02283
⊃
rdquor;
U+0201D
”
sigmav;
U+003C2
ς
supseteq;
U+02287
⊇
rdsh;
U+021B3
↳
sim;
U+0223C
∼
supseteqq;
U+02AC6
?
real;
U+0211C
ℜ
simdot;
U+02A6A
?
supsetneq;
U+0228B
⊋
realine;
U+0211B
ℛ
sime;
U+02243
≃
supsetneqq;
U+02ACC
?
realpart;
U+0211C
ℜ
simeq;
U+02243
≃
supsim;
U+02AC8
?
reals;
U+0211D
ℝ
simg;
U+02A9E
⪞
supsub;
U+02AD4
?
?
633
Name
Character Glyph
Name
Character Glyph
Name
Character Glyph
supsup;
U+02AD6
?
ubrcy;
U+0045E
ў
vert;
U+0007C
|
swArr;
U+021D9
⇙
ubreve;
U+0016D
ŭ
vfr;
U+1D533
?
swarhk;
U+02926
?
ucirc;
U+000FB
û
vltri;
U+022B2
⊲
swarr;
U+02199
↙
ucirc
U+000FB
û
vopf;
U+1D567
swarrow;
U+02199
↙
ucy;
U+00443
у
vprop;
U+0221D
∝
swnwar;
U+0292A
?
udarr;
U+021C5
⇅
vrtri;
U+022B3
⊳
szlig;
U+000DF
ß
udblac;
U+00171
ű
vscr;
U+1D4CB
?
szlig
U+000DF
ß
udhar;
U+0296E
?
vzigzag;
U+0299A
?
target;
U+02316
?
ufisht;
U+0297E
?
wcirc;
U+00175
ŵ
tau;
U+003C4
τ
ufr;
U+1D532
?
wedbar;
U+02A5F
?
tbrk;
U+023B4
?
ugrave;
U+000F9
ù
wedge;
U+02227
∧
tcaron;
U+00165
ť
ugrave
U+000F9
ù
wedgeq;
U+02259
≙
tcedil;
U+00163
ţ
uharl;
U+021BF
↿
weierp;
U+02118
tcy;
U+00442
т
uharr;
U+021BE
↾
wfr;
U+1D534
?
tdot;
U+020DB
◌?
uhblk;
U+02580
▀
wopf;
U+1D568
𝕨
telrec;
U+02315
?
ulcorn;
U+0231C
⌜
wp;
U+02118
℘
tfr;
U+1D531
?
ulcorner;
U+0231C
⌜
wr;
U+02240
≀
there4;
U+02234
∴
ulcrop;
U+0230F
⌏
wreath;
U+02240
≀
therefore;
U+02234
∴
ultri;
U+025F8
◸
wscr;
U+1D4CC
?
theta;
U+003B8
θ
umacr;
U+0016B
ū
xcap;
U+022C2
⋂
thetasym;
U+003D1
ϑ
uml;
U+000A8
¨
xcirc;
U+025EF
◯
thetav;
U+003D1
ϑ
uml
U+000A8
¨
xcup;
U+022C3
⋃
thickapprox;
U+02248
≈
uogon;
U+00173
ų
xdtri;
U+025BD
▽
thicksim;
U+0223C
∼
uopf;
U+1D566
𝕦
xfr;
U+1D535
?
thinsp;
U+02009
uparrow;
U+02191
↑
xhArr;
U+027FA
⟺
thkap;
U+02248
≈
updownarrow;
U+02195
↕
xharr;
U+027F7
⟷
thksim;
U+0223C
∼
upharpoonleft;
U+021BF
↿
xi;
U+003BE
ξ
thorn;
U+000FE
þ
upharpoonright;
U+021BE
↾
xlArr;
U+027F8
⟸
thorn
U+000FE
þ
uplus;
U+0228E
⊎
xlarr;
U+027F5
⟵
tilde;
U+002DC
˜
upsi;
U+003C5
υ
xmap;
U+027FC
⟼
times;
U+000D7
×
upsih;
U+003D2
ϒ
xnis;
U+022FB
⋻
times
U+000D7
×
upsilon;
U+003C5
υ
xodot;
U+02A00
⨀
timesb;
U+022A0
⊠
upuparrows;
U+021C8
⇈
xopf;
U+1D569
𝕩
timesbar;
U+02A31
?
urcorn;
U+0231D
⌝
xoplus;
U+02A01
⨁
timesd;
U+02A30
?
urcorner;
U+0231D
⌝
xotime;
U+02A02
⨂
tint;
U+0222D
∭
urcrop;
U+0230E
⌎
xrArr;
U+027F9
⟹
toea;
U+02928
?
uring;
U+0016F
ů
xrarr;
U+027F6
⟶
top;
U+022A4
⊤
urtri;
U+025F9
◹
xscr;
U+1D4CD
?
topbot;
U+02336
?
uscr;
U+1D4CA
?
xsqcup;
U+02A06
topcir;
U+02AF1
?
utdot;
U+022F0
⋰
xuplus;
U+02A04
?
topf;
U+1D565
𝕥
utilde;
U+00169
ũ
xutri;
U+025B3
△
topfork;
U+02ADA
?
utri;
U+025B5
▵
xvee;
U+022C1
⋁
tosa;
U+02929
?
utrif;
U+025B4
▴
xwedge;
U+022C0
⋀
tprime;
U+02034
‴
uuarr;
U+021C8
⇈
yacute;
U+000FD
ý
trade;
U+02122
™
uuml;
U+000FC
ü
yacute
U+000FD
ý
triangle;
U+025B5
▵
uuml
U+000FC
ü
yacy;
U+0044F
я
triangledown;
U+025BF
▿
uwangle;
U+029A7
?
ycirc;
U+00177
ŷ
triangleleft;
U+025C3
◃
vArr;
U+021D5
⇕
ycy;
U+0044B
ы
trianglelefteq;
U+022B4
⊴
vBar;
U+02AE8
?
yen;
U+000A5
¥
triangleq;
U+0225C
≜
vBarv;
U+02AE9
?
yen
U+000A5
¥
triangleright;
U+025B9
▹
vDash;
U+022A8
⊨
yfr;
U+1D536
?
trianglerighteq;
U+022B5
⊵
vangrt;
U+0299C
?
yicy;
U+00457
ї
tridot;
U+025EC
◬
varepsilon;
U+003F5
ϵ
yopf;
U+1D56A
𝕪
trie;
U+0225C
≜
varkappa;
U+003F0
ϰ
yscr;
U+1D4CE
?
triminus;
U+02A3A
?
varnothing;
U+02205
∅
yucy;
U+0044E
ю
triplus;
U+02A39
?
varphi;
U+003D5
ϕ
yuml;
U+000FF
ÿ
trisb;
U+029CD
?
varpi;
U+003D6
ϖ
yuml
U+000FF
ÿ
tritime;
U+02A3B
?
varpropto;
U+0221D
∝
zacute;
U+0017A
trpezium;
U+023E2
?
varr;
U+02195
↕
zcaron;
U+0017E
ž
tscr;
U+1D4C9
?
varrho;
U+003F1
ϱ
zcy;
U+00437
з
tscy;
U+00446
ц
varsigma;
U+003C2
ς
zdot;
U+0017C
ż
tshcy;
U+0045B
ћ
vartheta;
U+003D1
ϑ
zeetrf;
U+02128
ℨ
tstrok;
U+00167
ŧ
vartriangleleft;
U+022B2
⊲
zeta;
U+003B6
ζ
twixt;
U+0226C
≬
vartriangleright;
U+022B3
⊳
zfr;
U+1D537
?
twoheadleftarrow;
U+0219E
↞
vcy;
U+00432
в
zhcy;
U+00436
ж
twoheadrightarrow;
U+021A0
↠
vdash;
U+022A2
⊢
zigrarr;
U+021DD
⇝
uArr;
U+021D1
⇑
vee;
U+02228
∨
zopf;
U+1D56B
𝕫
uHar;
U+02963
?
veebar;
U+022BB
⊻
zscr;
U+1D4CF
?
uacute;
U+000FA
ú
veeeq;
U+0225A
≚
zwj;
U+0200D
uacute
U+000FA
ú
vellip;
U+022EE
⋮
zwnj;
U+0200C
uarr;
U+02191
↑
verbar;
U+0007C
|
𝕧
℘
?
ź
The glyphs displayed above are non-normative. Refer to the Unicode specifications for formal definitions of the
characters listed above.
634
11 The XHTML syntax
Note: This section only describes the rules for XML resources. Rules for text/html p678 resources
are discussed in the section above entitled "The HTML syntax p547 ".
11.1 Writing XHTML documents
The syntax for using HTML with XML, whether in XHTML documents or embedded in other XML documents, is
defined in the XML and Namespaces in XML specifications. [XML] p705 [XMLNS] p705
This specification does not define any syntax-level requirements beyond those defined for XML proper.
XML documents may contain a DOCTYPE if desired, but this is not required to conform to this specification. This
specification does not define a public or system identifier, nor provide a format DTD.
Note: According to the XML specification, XML processors are not guaranteed to process the
external DTD subset referenced in the DOCTYPE. This means, for example, that using entity
references for characters in XHTML documents is unsafe if they are defined in an external file
(except for <, >, &, " and ').
11.2 Parsing XHTML documents
This section describes the relationship between XML and the DOM, with a particular emphasis on how this
interacts with HTML.
An XML parser, for the purposes of this specification, is a construct that follows the rules given in the XML
specification to map a string of bytes or characters into a Document p31 object.
An XML parser p635 is either associated with a Document p31 object when it is created, or creates one implicitly.
This Document p31 must then be populated with DOM nodes that represent the tree structure of the input passed to
the parser, as defined by the XML specification, the Namespaces in XML specification, and the DOM Core
specification. DOM mutation events must not fire for the operations that the XML parser p635 performs on the
Document p31 's tree, but the user agent must act as if elements and attributes were individually appended and set
respectively so as to trigger rules in this specification regarding what happens when an element in inserted into a
document or has its attributes set. [XML] p705 [XMLNS] p705 [DOMCORE] p701 [DOMEVENTS] p701
Between the time an element's start tag is parsed and the time either the element's end tag is parsed on the
parser detects a well-formedness error, the user agent must act as if the element was in a stack of open
elements p563 .
Note: This is used by the object p208 element to avoid instantiating plugins before the param p213
element children have been parsed.
This specification provides the following additional information that user agents should use when retrieving an
external entity: the public identifiers given in the following list all correspond to the URL given by this link.
•
•
•
•
•
•
•
•
•
-//W3C//DTD XHTML 1.0 Transitional//EN
-//W3C//DTD XHTML 1.1//EN
-//W3C//DTD XHTML 1.0 Strict//EN
-//W3C//DTD XHTML 1.0 Frameset//EN
-//W3C//DTD XHTML Basic 1.0//EN
-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN
-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN
-//W3C//DTD MathML 2.0//EN
-//WAPFORUM//DTD XHTML Mobile 1.0//EN
Furthermore, user agents should attempt to retrieve the above external entity's content when one of the above
public identifiers is used, and should not attempt to retrieve any other external entity's content.
Note: This is not strictly a violation p17 of the XML specification, but it does contradict the spirit
of the XML specification's requirements. This is motivated by a desire for user agents to all
handle entities in an interoperable fashion without requiring any network access for handling
external subsets. [XML] p705
When an XML parser p635 creates a script p122 element, it must be marked as being "parser-inserted" p124 . If the
parser was originally created for the XML fragment parsing algorithm p637 , then the element must be marked as
"already started" p123 also. When the element's end tag is parsed, the user agent must run p124 the script p122
635
element. If this causes there to be a pending parsing-blocking script p125 , then the user agent must run the
following steps:
1.
Block this instance of the XML parser p635 , such that the event loop p489 will not run tasks p489 that invoke it.
2.
Spin the event loop p490 until there is no style sheet blocking scripts p122 and the pending parsing-blocking
script p125 's "ready to be parser-executed" p124 flag is set.
3.
Unblock this instance of the XML parser p635 , such that tasks p489 that invoke it can again be run.
4.
Execute p125 the pending parsing-blocking script p125 .
5.
There is no longer a pending parsing-blocking script p125 .
Note: Since the document.write() p101 API is not available for XML documents p71 , much of the
complexity in the HTML parser p554 is not needed in the XML parser p635 .
Certain algorithms in this specification spoon-feed the parser characters one string at a time. In such cases, the
XML parser p635 must act as it would have if faced with a single string consisting of the concatenation of all those
characters.
When an XML parser p635 reaches the end of its input, it must stop parsing p618 , following the same rules as the
HTML parser p554 .
For the purposes of conformance checkers, if a resource is determined to be in the XHTML syntax p635 , then it is an
XML document p71 .
11.3 Serializing XHTML fragments
The XML fragment serialization algorithm for a Document p31 or Element p31 node either returns a fragment of
XML that represents that node or raises an exception.
For Document p31 s, the algorithm must return a string in the form of a document entity, if none of the error cases
below apply.
For Element p31 s, the algorithm must return a string in the form of an internal general parsed entity, if none of the
error cases below apply.
In both cases, the string returned must be XML namespace-well-formed and must be an isomorphic serialization of
all of that node's child nodes, in tree order p27 . User agents may adjust prefixes and namespace declarations in the
serialization (and indeed might be forced to do so in some cases to obtain namespace-well-formed XML). User
agents may use a combination of regular text, character references, and CDATA sections to represent text
nodes p27 in the DOM (and indeed might be forced to use representations that don't match the DOM's, e.g. if a
CDATASection p31 node contains the string "]]>").
For Element p31 s, if any of the elements in the serialization are in no namespace, the default namespace in scope
for those elements must be explicitly declared as the empty string. (This doesn't apply in the Document p31 case.)
[XML] p705 [XMLNS] p705
For the purposes of this section, an internal general parsed entity is considered XML namespace-well-formed if a
document consisting of an element with no namespace declarations whose contents are the internal general
parsed entity would itself be XML namespace-well-formed.
If any of the following error cases are found in the DOM subtree being serialized, then the algorithm must raise an
INVALID_STATE_ERR p70 exception instead of returning a string:
636
•
A Document p31 node with no child element nodes.
•
A DocumentType p31 node that has an external subset public identifier that contains characters that are
not matched by the XML PubidChar production. [XML] p705
•
A DocumentType p31 node that has an external subset system identifier that contains both a U+0022
QUOTATION MARK (") and a U+0027 APOSTROPHE (') or that contains characters that are not matched
by the XML Char production. [XML] p705
•
A node with a local name containing a U+003A COLON (:).
•
A node with a local name that does not match the XML Name production. [XML] p705
•
An Attr p31 node with no namespace whose local name is the lowercase string "xmlns". [XMLNS] p705
•
An Element p31 node with two or more attributes with the same local name and namespace.
•
An Attr p31 node, Text p31 node, CDATASection p31 node, Comment p31 node, or ProcessingInstruction p31
node whose data contains characters that are not matched by the XML Char production. [XML] p705
•
A Comment p31 node whose data contains two adjacent U+002D HYPHEN-MINUS characters (-) or ends
with such a character.
•
A ProcessingInstruction p31 node whose target name is an ASCII case-insensitive p33 match for the
string "xml".
•
A ProcessingInstruction p31 node whose target name contains a U+003A COLON (:).
•
A ProcessingInstruction p31 node whose data contains the string "?>".
Note: These are the only ways to make a DOM unserializable. The DOM enforces all the other
XML constraints; for example, trying to append two elements to a Document p31 node will raise a
HIERARCHY_REQUEST_ERR p70 exception.
11.4 Parsing XHTML fragments
The XML fragment parsing algorithm for either returns a Document p31 or raises a SYNTAX_ERR p70 exception.
Given a string input and an optional context element context, the algorithm is as follows:
1.
Create a new XML parser p635 .
2.
If there is a context element, feed the parser p636 just created the string corresponding to the start tag of
that element, declaring all the namespace prefixes that are in scope on that element in the DOM, as well
as declaring the default namespace (if any) that is in scope on that element in the DOM.
A namespace prefix is in scope if the DOM Core lookupNamespaceURI() method on the element would
return a non-null value for that prefix.
The default namespace is the namespace for which the DOM Core isDefaultNamespace() method on
the element would return true.
Note: If there is a context element, no DOCTYPE is passed to the parser, and therefore
no external subset is referenced, and therefore no entities will be recognized.
3.
Feed the parser p636 just created the string input.
4.
If there is a context element, feed the parser p636 just created the string corresponding to the end tag of
that element.
5.
If there is an XML well-formedness or XML namespace well-formedness error, then raise a SYNTAX_ERR p70
exception and abort these steps.
6.
If there is a context element, then return the child nodes of the root element of the resulting
Document p31 , in tree order p27 .
Otherwise, return the children of the Document p31 object, in tree order p27 .
637
12 Rendering
User agents are not required to present HTML documents in any particular way. However, this section provides a
set of suggestions for rendering HTML documents that, if followed, are likely to lead to a user experience that
closely resembles the experience intended by the documents' authors. So as to avoid confusion regarding the
normativity of this section, RFC2119 terms have not been used. Instead, the term "expected" is used to indicate
behavior that will lead to this experience.
12.1 Introduction
In general, user agents are expected to support CSS, and many of the suggestions in this section are expressed in
CSS terms. User agents that use other presentation mechanisms can derive their expected behavior by translating
from the CSS rules given in this section.
In the absence of style-layer rules to the contrary (e.g. author style sheets), user agents are expected to render an
element so that it conveys to the user the meaning that the element represents, as described by this
specification.
The suggestions in this section generally assume a visual output medium with a resolution of 96dpi or greater, but
HTML is intended to apply to multiple media (it is a media-independent language). User agents are encouraged to
adapt the suggestions in this section to their target media.
An element is being rendered if it is in a Document p27 , either its parent node is itself being rendered p638 or it is
the Document p31 node, and it is not explicitly excluded from the rendering using either:
•
•
•
the CSS 'display' property's 'none' value, or
the 'visibility' property's 'collapse' value unless it is being treated as equivalent to the 'hidden' value, or
some equivalent in other styling languages.
Note: Just being off-screen does not mean the element is not being rendered p638 . The presence
of the hidden p508 attribute normally means the element is not being rendered p638 , though this
might be overriden by the style sheets.
12.2 The CSS user agent style sheet and presentational hints
12.2.1 Introduction
The CSS rules given in these subsections are, except where otherwise specified, expected to be used as part of the
user-agent level style sheet defaults for all documents that contain HTML elements p26 .
Some rules are intended for the author-level zero-specificity presentational hints part of the CSS cascade; these
are explicitly called out as presentational hints.
Some of the rules regarding left and right margins are given here as appropriate for elements whose 'direction'
property is 'ltr', and are expected to be flipped around on elements whose 'direction' property is 'rtl'. These are
marked "LTR-specific".
For the purpose of the rules marked "case-sensitive", user agents are expected to use case-sensitive matching of
attribute values rather than case-insensitive matching, regardless of whether a case-insensitive matching is
normally required for the given attribute.
Similarly, for the purpose of the rules marked "case-insensitive", user agents are expected to use ASCII caseinsensitive p33 matching of attribute values rather than case-sensitive matching, even for attributes in XHTML
documents.
Note: These markings only affect the handling of attribute values, not attribute names or
element names.
When the text below says that an attribute attribute on an element element maps to the pixel length property
(or properties) properties, it means that if element has an attribute attribute set, and parsing that attribute's value
using the rules for parsing non-negative integers p35 doesn't generate an error, then the user agent is expected to
use the parsed value as a pixel length for a presentational hint p638 for properties.
When the text below says that an attribute attribute on an element element maps to the dimension property
(or properties) properties, it means that if element has an attribute attribute set, and parsing that attribute's value
using the rules for parsing dimension values p37 doesn't generate an error, then the user agent is expected to use
the parsed dimension as the value for a presentational hint p638 for properties, with the value given as a pixel
638
length if the dimension was an integer, and with the value given as a percentage if the dimension was a
percentage.
12.2.2 Display types
@namespace url(http://www.w3.org/1999/xhtml);
[hidden], area, base, basefont, command, datalist, head,
input[type=hidden], link, menu[type=context], meta, noembed, noframes,
param, rp, script, source, style, title { /* case-insensitive */
display: none;
}
address, article, aside, blockquote, body, center, dd, dir, div, dl,
dt, figure, figcaption, footer, form, h1, h2, h3, h4, h5, h6, header,
hgroup, hr, html, legend, listing, menu, nav, ol, p, plaintext, pre,
section, summary, ul, xmp { display: block; }
table { display: table; }
caption { display: table-caption; }
colgroup { display: table-column-group; }
col { display: table-column; }
thead { display: table-header-group; }
tbody { display: table-row-group; }
tfoot { display: table-footer-group; }
tr { display: table-row; }
td, th { display: table-cell; }
li { display: list-item; }
ruby { display: ruby; }
rt { display: ruby-text; }
For the purposes of the CSS table model, the col p279 element is expected to be treated as if it was present as
many times as its span p279 attribute specifies p35 .
For the purposes of the CSS table model, the colgroup p278 element, if it contains no col p279 element, is expected
to be treated as if it had as many such children as its span p278 attribute specifies p35 .
For the purposes of the CSS table model, the colspan p284 and rowspan p284 attributes on td p282 and th p283 elements
are expected to provide p35 the special knowledge regarding cells spanning rows and columns.
For the purposes of the CSS ruby model, runs of children of ruby p177 elements that are not rt p179 or rp p179
elements are expected to be wrapped in anonymous boxes whose 'display' property has the value 'ruby-base'.
User agents that do not support correct ruby rendering are expected to render parentheses around the text of
rt p179 elements in the absence of rp p179 elements.
The br p181 element is expected to render as if its contents were a single U+000A LINE FEED (LF) character and its
'white-space' property was 'pre'. User agents are expected to support the 'clear' property on inline elements (in
order to render br p181 elements with clear p664 attributes) in the manner described in the non-normative note to
this effect in CSS2.1.
The user agent is expected to hide noscript p129 elements for whom scripting is enabled p487 , irrespective of CSS
rules.
In HTML documents p71 , the user agent is expected to hide form p297 elements that are children of table p271 ,
thead p280 , tbody p279 , tfoot p280 , or tr p281 elements, irrespective of CSS rules.
12.2.3 Margins and padding
@namespace url(http://www.w3.org/1999/xhtml);
blockquote, dir, dl, figure, listing, menu, ol, p, plaintext,
pre, ul, xmp {
margin-top: 1em; margin-bottom: 1em;
}
dir dir, dir dl, dir menu, dir ol, dir ul,
639
dl dir, dl dl, dl menu, dl ol, dl ul,
menu dir, menu dl, menu menu, menu ol, menu ul,
ol dir, ol dl, ol menu, ol ol, ol ul,
ul dir, ul dl, ul menu, ul ol, ul ul {
margin-top: 0; margin-bottom: 0;
}
h1
h2
h3
h4
h5
h6
{
{
{
{
{
{
margin-top:
margin-top:
margin-top:
margin-top:
margin-top:
margin-top:
0.67em;
0.83em;
1.00em;
1.33em;
1.67em;
2.33em;
margin-bottom;
margin-bottom;
margin-bottom;
margin-bottom;
margin-bottom;
margin-bottom;
0.67em;
0.83em;
1.00em;
1.33em;
1.67em;
2.33em;
}
}
}
}
}
}
dd { margin-left: 40px; } /* LTR-specific: use 'margin-right' for rtl elements */
dir, menu, ol, ul { padding-left: 40px; } /* LTR-specific: use 'padding-right' for rtl
elements */
blockquote, figure { margin-left: 40px; margin-right: 40px; }
table { border-spacing: 2px; border-collapse: separate; }
td, th { padding: 1px; }
The article p136 , aside p137 , nav p134 , and section p133 elements are expected to affect the margins of h1 p139
elements, based on the nesting depth. If x is a selector that matches elements that are either article p136 ,
aside p137 , nav p134 , or section p133 elements, then the following rules capture what is expected:
@namespace url(http://www.w3.org/1999/xhtml);
x
x
x
x
x
h1 { margin-top: 0.83em; margin-bottom: 0.83em; }
x h1 { margin-top: 1.00em; margin-bottom: 1.00em; }
x x h1 { margin-top: 1.33em; margin-bottom: 1.33em; }
x x x h1 { margin-top: 1.67em; margin-bottom: 1.67em; }
x x x x h1 { margin-top: 2.33em; margin-bottom: 2.33em; }
For each property in the table below, given a body p131 element, the first attribute that exists maps to the pixel
length property p638 on the body p131 element. If none of the attributes for a property are found, or if the value of the
attribute that was found cannot be parsed successfully, then a default value of 8px is expected to be used for that
property instead.
Property
'margin-top'
Source
body
p131
element's marginheight
p664
attribute
The body p131 element's container frame element p640 's marginheight p664 attribute
body p131 element's topmargin attribute
'margin-right'
body p131 element's marginwidth p664 attribute
The body p131 element's container frame element p640 's marginwidth p664 attribute
body p131 element's rightmargin attribute
'margin-bottom' body p131 element's marginheight p664 attribute
The body p131 element's container frame element p640 's marginheight p664 attribute
body p131 element's topmargin attribute
'margin-left'
body p131 element's marginwidth p664 attribute
The body p131 element's container frame element p640 's marginwidth p664 attribute
body p131 element's rightmargin attribute
If the body p131 element's Document p31 's browsing context p439 is a nested browsing context p439 , and the browsing
context container p439 of that nested browsing context p439 is a frame p668 or iframe p199 element, then the container
frame element of the body p131 element is that frame p668 or iframe p199 element. Otherwise, there is no container
frame element p640 .
⚠Warning! The above requirements imply that a page can change the margins of another page
(including one from another origin p449 ) using, for example, an iframe p199 . This is potentially a security
risk, as it might in some cases allow an attack to contrive a situation in which a page is rendered not
as the author intended, possibly for the purposes of phishing or otherwise misleading the user.
If the Document p31 has a root element p27 , and the Document p31 's browsing context p439 is a nested browsing
context p439 , and the browsing context container p439 of that nested browsing context p439 is a frame p668 or iframe p199
element, and that element has a scrolling attribute, then the user agent is expected to compare the value of the
640
attribute in an ASCII case-insensitive p33 manner to the values in the first column of the following table, and if one
of them matches, then the user agent is expected to treat that attribute as a presentational hint p638 for the
aforementioned root element's 'overflow' property, setting it to the value given in the corresponding cell on the
same row in the second column:
Attribute value 'overflow' value
on
'scroll'
scroll
'scroll'
yes
'scroll'
off
'hidden'
noscroll
'hidden'
no
'hidden'
auto
'auto'
The table p271 element's cellspacing p665 attribute maps to the pixel length property p638 'border-spacing' on the
element.
The table p271 element's cellpadding p665 attribute maps to the pixel length properties p638 'padding-top', 'paddingright', 'padding-bottom', and 'padding-left' of any td p282 and th p283 elements that have corresponding cells p285 in
the table p285 corresponding to the table p271 element.
The table p271 element's hspace attribute maps to the dimension properties p638 'margin-left' and 'margin-right' on
the table p271 element.
The table p271 element's vspace attribute maps to the dimension properties p638 'margin-top' and 'margin-bottom'
on the table p271 element.
The table p271 element's height attribute maps to the dimension property p638 'height' on the table p271 element.
The table p271 element's width p665 attribute maps to the dimension property p638 'width' on the table p271 element.
The col p279 element's width p664 attribute maps to the dimension property p638 'width' on the col p279 element.
The tr p281 element's height attribute maps to the dimension property p638 'height' on the tr p281 element.
The td p282 and th p283 elements' height p665 attributes map to the dimension property p638 'height' on the element.
The td p282 and th p283 elements' width p665 attributes map to the dimension property p638 'width' on the element.
In quirks mode p75 , the following rules are also expected to apply:
@namespace url(http://www.w3.org/1999/xhtml);
form { margin-bottom: 1em; }
When a Document p31 is in quirks mode p75 , margins on HTML elements p26 at the top or bottom of body p131 , td p282 , or
th p283 elements are expected to be collapsed to zero.
12.2.4 Alignment
@namespace url(http://www.w3.org/1999/xhtml);
thead, tbody, tfoot, table > tr { vertical-align: middle; }
tr, td, th { vertical-align: inherit; }
sub { vertical-align: sub; }
sup { vertical-align: super; }
th { text-align: center; }
The following rules are also expected to apply, as presentational hints p638 :
@namespace url(http://www.w3.org/1999/xhtml);
table[align=left] { float: left; } /* case-insensitive */
table[align=right] { float: right; } /* case-insensitive */
table[align=center], table[align=abscenter],
table[align=absmiddle], table[align=middle] { /* case-insensitive */
margin-left: auto; margin-right: auto;
641
}
caption[align=bottom] { caption-side: bottom; } /* case-insensitive */
p[align=left], h1[align=left], h2[align=left], h3[align=left],
h4[align=left], h5[align=left], h6[align=left] { /* case-insensitive */
text-align: left;
}
p[align=right], h1[align=right], h2[align=right], h3[align=right],
h4[align=right], h5[align=right], h6[align=right] { /* case-insensitive */
text-align: right;
}
p[align=center], h1[align=center], h2[align=center], h3[align=center],
h4[align=center], h5[align=center], h6[align=center] { /* case-insensitive */
text-align: center;
}
p[align=justify], h1[align=justify], h2[align=justify], h3[align=justify],
h4[align=justify], h5[align=justify], h6[align=justify] { /* case-insensitive */
text-align: justify;
}
col[valign=top], thead[valign=top], tbody[valign=top],
tfoot[valign=top], tr[valign=top], td[valign=top], th[valign=top] { /* case-insensitive
*/
vertical-align: top;
}
col[valign=middle], thead[valign=middle], tbody[valign=middle],
tfoot[valign=middle], tr[valign=middle], td[valign=middle], th[valign=middle] { /*
case-insensitive */
vertical-align: middle;
}
col[valign=bottom], thead[valign=bottom], tbody[valign=bottom],
tfoot[valign=bottom], tr[valign=bottom], td[valign=bottom], th[valign=bottom] { /*
case-insensitive */
vertical-align: bottom;
}
col[valign=baseline], thead[valign=baseline], tbody[valign=baseline],
tfoot[valign=baseline], tr[valign=baseline], td[valign=baseline], th[valign=baseline] {
/* case-insensitive */
vertical-align: baseline;
}
The center p661 element, the caption p277 element unless specified otherwise below, and the div p159 , thead p280 ,
tbody p279 , tfoot p280 , tr p281 , td p282 , and th p283 elements when they have an align p664 attribute whose value is an
ASCII case-insensitive p33 match for the string "center", are expected to center text within themselves, as if they
had their 'text-align' property set to 'center' in a presentational hint p638 , and to align descendants p642 to the center.
The div p159 , caption p277 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , and th p283 elements, when they have an
align attribute whose value is an ASCII case-insensitive p33 match for the string "left", are expected to left-align
text within themselves, as if they had their 'text-align' property set to 'left' in a presentational hint p638 , and to align
descendants p642 to the left.
The div p159 , caption p277 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , and th p283 elements, when they have an
align attribute whose value is an ASCII case-insensitive p33 match for the string "right", are expected to rightalign text within themselves, as if they had their 'text-align' property set to 'right' in a presentational hint p638 , and
to align descendants p642 to the right.
The div p159 , caption p277 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , and th p283 elements, when they have an
align attribute whose value is an ASCII case-insensitive p33 match for the string "justify", are expected to fulljustify text within themselves, as if they had their 'text-align' property set to 'justify' in a presentational hint p638 ,
and to align descendants p642 to the left.
When a user agent is to align descendants of a node, the user agent is expected to align only those
descendants that have both their 'margin-left' and 'margin-right' properties computing to a value other than 'auto',
that are over-constrained and that have one of those two margins with a used value forced to a greater value, and
that do not themselves have an applicable align attribute. When multiple elements are to align p642 a particular
descendant, the most deeply nested such element is expected to override the others.
642
12.2.5 Fonts and colors
@namespace url(http://www.w3.org/1999/xhtml);
address, cite, dfn, em, i, var { font-style: italic; }
b, strong, th { font-weight: bold; }
code, kbd, listing, plaintext, pre, samp, tt, xmp { font-family: monospace; }
h1 { font-size: 2.00em; font-weight: bold; }
h2 { font-size: 1.50em; font-weight: bold; }
h3 { font-size: 1.17em; font-weight: bold; }
h4 { font-size: 1.00em; font-weight: bold; }
h5 { font-size: 0.83em; font-weight: bold; }
h6 { font-size: 0.67em; font-weight: bold; }
big { font-size: larger; }
small, sub, sup { font-size: smaller; }
sub, sup { line-height: normal; }
:link { color: blue; }
:visited { color: purple; }
mark { background: yellow; color: black; }
table, td, th { border-color: gray; }
thead, tbody, tfoot, tr { border-color: inherit; }
table[rules=none], table[rules=groups], table[rules=rows],
table[rules=cols], table[rules=all], table[frame=void],
table[frame=above], table[frame=below], table[frame=hsides],
table[frame=lhs], table[frame=rhs], table[frame=vsides],
table[frame=box], table[frame=border],
table[rules=none] > tr > td, table[rules=none] > tr > th,
table[rules=groups] > tr > td, table[rules=groups] > tr > th,
table[rules=rows] > tr > td, table[rules=rows] > tr > th,
table[rules=cols] > tr > td, table[rules=cols] > tr > th,
table[rules=all] > tr > td, table[rules=all] > tr > th,
table[rules=none] > thead > tr > td, table[rules=none] > thead > tr > th,
table[rules=groups] > thead > tr > td, table[rules=groups] > thead > tr > th,
table[rules=rows] > thead > tr > td, table[rules=rows] > thead > tr > th,
table[rules=cols] > thead > tr > td, table[rules=cols] > thead > tr > th,
table[rules=all] > thead > tr > td, table[rules=all] > thead > tr > th,
table[rules=none] > tbody > tr > td, table[rules=none] > tbody > tr > th,
table[rules=groups] > tbody > tr > td, table[rules=groups] > tbody > tr > th,
table[rules=rows] > tbody > tr > td, table[rules=rows] > tbody > tr > th,
table[rules=cols] > tbody > tr > td, table[rules=cols] > tbody > tr > th,
table[rules=all] > tbody > tr > td, table[rules=all] > tbody > tr > th,
table[rules=none] > tfoot > tr > td, table[rules=none] > tfoot > tr > th,
table[rules=groups] > tfoot > tr > td, table[rules=groups] > tfoot > tr > th,
table[rules=rows] > tfoot > tr > td, table[rules=rows] > tfoot > tr > th,
table[rules=cols] > tfoot > tr > td, table[rules=cols] > tfoot > tr > th,
table[rules=all] > tfoot > tr > td, table[rules=all] > tfoot > tr > th { /*
case-insensitive */
border-color: black;
}
The initial value for the 'color' property is expected to be black. The initial value for the 'background-color'
property is expected to be 'transparent'. The canvas's background is expected to be white.
The article p136 , aside p137 , nav p134 , and section p133 elements are expected to affect the font size of h1 p139
elements, based on the nesting depth. If x is a selector that matches elements that are either article p136 ,
aside p137 , nav p134 , or section p133 elements, then the following rules capture what is expected:
@namespace url(http://www.w3.org/1999/xhtml);
x
x
x
x
x
h1 { font-size: 1.50em; }
x h1 { font-size: 1.17em; }
x x h1 { font-size: 1.00em; }
x x x h1 { font-size: 0.83em; }
x x x x h1 { font-size: 0.67em; }
643
When a body p131 , table p271 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , or th p283 element has a background p665
attribute set to a non-empty value, the new value is expected to be resolved p51 relative to the element, and if this
is successful, the user agent is expected to treat the attribute as a presentational hint p638 setting the element's
'background-image' property to the resulting absolute URL p52 .
When a body p131 , table p271 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , or th p283 element has a bgcolor attribute
set, the new value is expected to be parsed using the rules for parsing a legacy color value p48 , and if that does not
return an error, the user agent is expected to treat the attribute as a presentational hint p638 setting the element's
'background-color' property to the resulting color.
When a body p131 element has a text p664 attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the element's 'color' property to the resulting color.
When a body p131 element has a link p664 attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the 'color' property of any element in the Document p31 matching the ':link' pseudoclass to the resulting color.
When a body p131 element has a vlink p664 attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the 'color' property of any element in the Document p31 matching the ':visited'
pseudo-class to the resulting color.
When a body p131 element has a alink p664 attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the 'color' property of any element in the Document p31 matching the ':active'
pseudo-class and either the ':link' pseudo-class or the ':visited' pseudo-class to the resulting color.
When a table p271 element has a bordercolor attribute, its value is expected to be parsed using the rules for
parsing a legacy color value p48 , and if that does not return an error, the user agent is expected to treat the
attribute as a presentational hint p638 setting the element's 'border-top-color', 'border-right-color', 'border-bottomcolor', and 'border-right-color' properties to the resulting color.
When a font p661 element has a color attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the element's 'color' property to the resulting color.
When a font p661 element has a face attribute, the user agent is expected to treat the attribute as a presentational
hint p638 setting the element's 'font-family' property to the attribute's value.
When a font p661 element has a size attribute, the user agent is expected to use the following steps to treat the
attribute as a presentational hint p638 setting the element's 'font-size' property:
644
1.
Let input be the attribute's value.
2.
Let position be a pointer into input, initially pointing at the start of the string.
3.
Skip whitespace p34 .
4.
If position is past the end of input, there is no presentational hint p638 . Abort these steps.
5.
If the character at position is a U+002B PLUS SIGN character (+), then let mode be relative-plus, and
advance position to the next character. Otherwise, if the character at position is a U+002D HYPHENMINUS character (-), then let mode be relative-minus, and advance position to the next character.
Otherwise, let mode be absolute.
6.
Collect a sequence of characters p34 in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), and
let the resulting sequence be digits.
7.
If digits is the empty string, there is no presentational hint p638 . Abort these steps.
8.
Interpret digits as a base-ten integer. Let value be the resulting number.
9.
If mode is relative-plus, then increment value by 3. If mode is relative-minus, then let value be the result
of subtracting value from 3.
10.
If value is greater than 7, let it be 7.
11.
If value is less than 1, let it be 1.
12.
Set 'font-size' to the keyword corresponding to the value of value according to the following table:
value 'font-size' keyword
1
xx-small
2
small
3
medium
4
large
5
x-large
6
xx-large
7
xxx-large
Notes
see below
The 'xxx-large' value is a non-CSS value used here to indicate a font size one "step" larger than 'xxlarge'.
12.2.6 Punctuation and decorations
@namespace url(http://www.w3.org/1999/xhtml);
:link, :visited, ins, u { text-decoration: underline; }
abbr[title], acronym[title] { text-decoration: dotted underline; }
del, s, strike { text-decoration: line-through; }
blink { text-decoration: blink; }
q:before { content: open-quote; }
q:after { content: close-quote; }
nobr { white-space: nowrap; }
listing, plaintext, pre, xmp { white-space: pre; }
ol { list-style-type: decimal; }
dir, menu, ul {
list-style-type: disc;
}
dir dl, dir menu, dir ul,
menu dl, menu menu, menu ul,
ol dl, ol menu, ol ul,
ul dl, ul menu, ul ul {
list-style-type: circle;
}
dir dir dl, dir dir menu, dir dir ul,
dir menu dl, dir menu menu, dir menu ul,
dir ol dl, dir ol menu, dir ol ul,
dir ul dl, dir ul menu, dir ul ul,
menu dir dl, menu dir menu, menu dir ul,
menu menu dl, menu menu menu, menu menu ul,
menu ol dl, menu ol menu, menu ol ul,
menu ul dl, menu ul menu, menu ul ul,
ol dir dl, ol dir menu, ol dir ul,
ol menu dl, ol menu menu, ol menu ul,
ol ol dl, ol ol menu, ol ol ul,
ol ul dl, ol ul menu, ol ul ul,
ul dir dl, ul dir menu, ul dir ul,
ul menu dl, ul menu menu, ul menu ul,
ul ol dl, ul ol menu, ul ol ul,
ul ul dl, ul ul menu, ul ul ul {
list-style-type: square;
}
table { border-style: outset; }
td, th { border-style: inset; }
[dir=ltr] { direction: ltr; unicode-bidi: embed; } /* case-insensitive */
[dir=rtl] { direction: rtl; unicode-bidi: embed; } /* case-insensitive */
bdo[dir=ltr], bdo[dir=rtl] { unicode-bidi: bidi-override; } /* case-insensitive */
In addition, rules setting the 'quotes' property appropriately for the locales and languages understood by the user
are expected to be present.
645
The following rules are also expected to apply, as presentational hints p638 :
@namespace url(http://www.w3.org/1999/xhtml);
td[nowrap], th[nowrap] { white-space: nowrap; }
pre[wrap] { white-space: pre-wrap; }
br[clear=left] { clear: left; } /* case-insensitive */
br[clear=right] { clear: right; } /* case-insensitive */
br[clear=all], br[clear=both] { clear: both; } /* case-insensitive */
ol[type=1], li[type=1] { list-style-type: decimal; }
ol[type=a], li[type=a] { list-style-type: lower-alpha; } /*
ol[type=A], li[type=A] { list-style-type: upper-alpha; } /*
ol[type=i], li[type=i] { list-style-type: lower-roman; } /*
ol[type=I], li[type=I] { list-style-type: upper-roman; } /*
ul[type=disc], li[type=disc] { list-style-type: disc; }
ul[type=circle], li[type=circle] { list-style-type: circle;
ul[type=square], li[type=square] { list-style-type: square;
case-sensitive
case-sensitive
case-sensitive
case-sensitive
*/
*/
*/
*/
}
}
table[rules=none], table[rules=groups], table[rules=rows],
table[rules=cols], table[rules=all] {
border-style: none;
border-collapse: collapse;
}
table[frame=void] { border-style: hidden hidden hidden hidden;
table[frame=above] { border-style: solid hidden hidden hidden;
table[frame=below] { border-style: hidden hidden solid hidden;
table[frame=hsides] { border-style: solid hidden solid hidden;
table[frame=lhs] { border-style: hidden hidden hidden solid; }
table[frame=rhs] { border-style: hidden solid hidden hidden; }
table[frame=vsides] { border-style: hidden solid hidden solid;
table[frame=box],
table[frame=border] { border-style: solid solid solid solid; }
}
}
}
}
}
table[rules=none] > tr > td, table[rules=none] > tr > th,
table[rules=none] > thead > tr > td, table[rules=none] > thead > tr > th,
table[rules=none] > tbody > tr > td, table[rules=none] > tbody > tr > th,
table[rules=none] > tfoot > tr > td, table[rules=none] > tfoot > tr > th,
table[rules=groups] > tr > td, table[rules=groups] > tr > th,
table[rules=groups] > thead > tr > td, table[rules=groups] > thead > tr > th,
table[rules=groups] > tbody > tr > td, table[rules=groups] > tbody > tr > th,
table[rules=groups] > tfoot > tr > td, table[rules=groups] > tfoot > tr > th,
table[rules=rows] > tr > td, table[rules=rows] > tr > th,
table[rules=rows] > thead > tr > td, table[rules=rows] > thead > tr > th,
table[rules=rows] > tbody > tr > td, table[rules=rows] > tbody > tr > th,
table[rules=rows] > tfoot > tr > td, table[rules=rows] > tfoot > tr > th {
border-style: none;
}
table[rules=groups] > colgroup, table[rules=groups] > thead,
table[rules=groups] > tbody, table[rules=groups] > tfoot {
border-style: solid;
}
table[rules=rows] > tr, table[rules=rows] > thead > tr,
table[rules=rows] > tbody > tr, table[rules=rows] > tfoot > tr {
border-style: solid;
}
table[rules=cols] > tr > td, table[rules=cols] > tr > th,
table[rules=cols] > thead > tr > td, table[rules=cols] > thead > tr > th,
table[rules=cols] > tbody > tr > td, table[rules=cols] > tbody > tr > th,
table[rules=cols] > tfoot > tr > td, table[rules=cols] > tfoot > tr > th {
border-style: none solid none solid;
}
table[rules=all] > tr > td, table[rules=all] > tr > th,
table[rules=all] > thead > tr > td, table[rules=all] > thead > tr > th,
646
table[rules=all] > tbody > tr > td, table[rules=all] > tbody > tr > th,
table[rules=all] > tfoot > tr > td, table[rules=all] > tfoot > tr > th {
border-style: solid;
}
table[border] >
table[border] >
table[border] >
table[border] >
border-width:
}
tr > td, table[border] > tr > th,
thead > tr > td, table[border] > thead > tr > th,
tbody > tr > td, table[border] > tbody > tr > th,
tfoot > tr > td, table[border] > tfoot > tr > th {
1px;
When rendering li p154 elements, user agents are expected to use the ordinal value of the li p154 element to render
the counter in the list item marker.
The table p271 element's border p664 attribute maps to the pixel length properties p638 'border-top-width', 'borderright-width', 'border-bottom-width', 'border-left-width' on the element. If the attribute is present but parsing the
attribute's value using the rules for parsing non-negative integers p35 generates an error, a default value of 1px is
expected to be used for that property instead.
The wbr p181 element is expected to override the 'white-space' property and always provide a line-breaking
opportunity.
12.2.7 Resetting rules for inherited properties
The following rules are also expected to be in play, resetting certain properties to block inheritance by default.
@namespace url(http://www.w3.org/1999/xhtml);
table, input, select, option, optgroup, button, textarea, keygen {
text-indent: initial;
}
In quirks mode p75 , the following rules are also expected to apply:
@namespace url(http://www.w3.org/1999/xhtml);
table {
font-weight: initial;
font-style: initial;
font-variant: initial;
font-size: initial;
line-height: initial;
white-space: initial;
text-align: initial;
}
input { box-sizing: border-box; }
12.2.8 The hr p149 element
@namespace url(http://www.w3.org/1999/xhtml);
hr { color: gray; border-style: inset; border-width: 1px; }
The following rules are also expected to apply, as presentational hints p638 :
@namespace url(http://www.w3.org/1999/xhtml);
hr[align=left] { margin-left: 0; margin-right: auto; } /* case-insensitive */
hr[align=right] { margin-left: auto; margin-right: 0; } /* case-insensitive */
hr[align=center] { margin-left: auto; margin-right: auto; } /* case-insensitive */
hr[color], hr[noshade] { border-style: solid; }
If an hr p149 element has either a color p664 attribute or a noshade p664 attribute, and furthermore also has a size p664
attribute, and parsing that attribute's value using the rules for parsing non-negative integers p35 doesn't generate
647
an error, then the user agent is expected to use the parsed value divided by two as a pixel length for
presentational hints p638 for the properties 'border-top-width', 'border-right-width', 'border-bottom-width', and
'border-left-width' on the element.
Otherwise, if an hr p149 element has neither a color p664 attribute nor a noshade p664 attribute, but does have a
size p664 attribute, and parsing that attribute's value using the rules for parsing non-negative integers p35 doesn't
generate an error, then: if the parsed value is one, then the user agent is expected to use the attribute as a
presentational hint p638 setting the element's 'border-bottom-width' to 0; otherwise, if the parsed value is greater
than one, then the user agent is expected to use the parsed value minus two as a pixel length for presentational
hints p638 for the 'height' property on the element.
The width p664 attribute on an hr p149 element maps to the dimension property p638 'width' on the element.
When an hr p149 element has a color p664 attribute, its value is expected to be parsed using the rules for parsing a
legacy color value p48 , and if that does not return an error, the user agent is expected to treat the attribute as a
presentational hint p638 setting the element's 'color' property to the resulting color.
12.2.9 The fieldset p300 element
@namespace url(http://www.w3.org/1999/xhtml);
fieldset {
margin-left: 2px; margin-right: 2px;
border: groove 2px ThreeDFace;
padding: 0.35em 0.625em 0.75em;
}
The fieldset p300 element is expected to establish a new block formatting context.
The first legend p301 element child of a fieldset p300 element, if any, is expected to be rendered over the top
border edge of the fieldset p300 element. If the legend p301 element in question has an align p664 attribute, and its
value is an ASCII case-insensitive p33 match for one of the strings in the first column of the following table, then the
legend p301 is expected to be rendered horizontally aligned over the border edge in the position given in the
corresponding cell on the same row in the second column. If the attribute is absent or has a value that doesn't
match any of the cases in the table, then the position is expected to be on the right if the 'direction' property on
this element has a computed value of 'rtl', and on the left otherwise.
Attribute value Alignment position
left
On the left
right
On the right
center
In the middle
12.3 Replaced elements
12.3.1 Embedded content
The embed p205 , iframe p199 , and video p213 elements are expected to be treated as replaced elements.
A canvas p238 element that represents p638 embedded content p92 is expected to be treated as a replaced element.
Other canvas p238 elements are expected to be treated as ordinary elements in the rendering model.
An object p208 element that represents p638 an image, plugin, or nested browsing context p439 is expected to be
treated as a replaced element. Other object p208 elements are expected to be treated as ordinary elements in the
rendering model.
An applet p665 element that represents p638 a plugin p27 is expected to be treated as a replaced element. Other
applet p665 elements are expected to be treated as ordinary elements in the rendering model.
The audio p216 element, when it is exposing a user interface p235 , is expected to be treated as a replaced element
about one line high, as wide as is necessary to expose the user agent's user interface features. When an audio p216
element is not exposing a user interface p235 , the user agent is expected to hide it, irrespective of CSS rules.
Whether a video p213 element is exposing a user interface p235 is not expected to affect the size of the rendering;
controls are expected to be overlaid with the page content without causing any layout changes, and are expected
to disappear when the user does not need them.
When a video p213 element represents a poster frame or frame of video, the poster frame or frame of video is
expected to be rendered at the largest size that maintains the aspect ratio of that poster frame or frame of video
648
without being taller or wider than the video p213 element itself, and is expected to be centered in the video p213
element.
Note: Resizing video p213 and canvas p238 elements does not interrupt video playback or clear the
canvas.
The following CSS rules are expected to apply:
@namespace url(http://www.w3.org/1999/xhtml);
iframe { border: 2px inset; }
12.3.2 Images
When an img p186 element or an input p303 element when its type p304 attribute is in the Image Button p321 state
represents p638 an image, it is expected to be treated as a replaced element.
When an img p186 element or an input p303 element when its type p304 attribute is in the Image Button p321 state does
not represent p638 an image, but the element already has intrinsic dimensions (e.g. from the dimension
attributes p271 or CSS rules), and either the user agent has reason to believe that the image will become
available p187 and be rendered in due course or the Document p31 is in quirks mode p75 , the element is expected to be
treated as a replaced element whose content is the text that the element represents, if any, optionally alongside
an icon indicating that the image is being obtained. For input p303 elements, the text is expected to appear buttonlike to indicate that the element is a button p297 .
When an img p186 element represents p638 some text and the user agent does not expect this to change, the element
is expected to be treated as an inline element whose content is the text, optionally with an icon indicating that an
image is missing.
When an img p186 element represents p638 nothing and the user agent does not expect this to change, the element is
expected to not be rendered at all.
When an img p186 element might be a key part of the content, but neither the image nor any kind of alternative text
is available, and the user agent does not expect this to change, the element is expected to be treated as an inline
element whose content is an icon indicating that an image is missing.
When an input p303 element whose type p304 attribute is in the Image Button p321 state does not represent p638 an
image and the user agent does not expect this to change, the element is expected to be treated as a replaced
element consisting of a button whose content is the element's alternative text. The intrinsic dimensions of the
button are expected to be about one line in height and whatever width is necessary to render the text on one line.
The icons mentioned above are expected to be relatively small so as not to disrupt most text but be easily
clickable. In a visual environment, for instance, icons could be 16 pixels by 16 pixels square, or 1em by 1em if the
images are scalable. In an audio environment, the icon could be a short bleep. The icons are intended to indicate
to the user that they can be used to get to whatever options the UA provides for images, and, where appropriate,
are expected to provide access to the context menu that would have come up if the user interacted with the
actual image.
The following CSS rules are expected to apply when the Document p31 is in quirks mode p75 :
@namespace url(http://www.w3.org/1999/xhtml);
img[align=left] { margin-right: 3px; } /* case-insensitive */
img[align=right] { margin-left: 3px; } /* case-insensitive */
12.3.3 Attributes for embedded content and images
The following CSS rules are expected to apply as presentational hints p638 :
@namespace url(http://www.w3.org/1999/xhtml);
iframe[frameborder=0], iframe[frameborder=no] { border: none; } /* case-insensitive */
applet[align=left], embed[align=left], iframe[align=left],
img[align=left], input[type=image][align=left], object[align=left] { /* case-insensitive
*/
float: left;
649
}
applet[align=right], embed[align=right], iframe[align=right],
img[align=right], input[type=image][align=right], object[align=right] { /*
case-insensitive */
float: right;
}
applet[align=top], embed[align=top], iframe[align=top],
img[align=top], input[type=image][align=top], object[align=top] { /* case-insensitive */
vertical-align: top;
}
applet[align=bottom], embed[align=bottom], iframe[align=bottom],
img[align=bottom], input[type=image][align=bottom], object[align=bottom],
applet[align=baseline], embed[align=baseline], iframe[align=baseline],
img[align=baseline], input[type=image][align=baseline], object[align=baseline] { /*
case-insensitive */
vertical-align: baseline;
}
applet[align=texttop], embed[align=texttop], iframe[align=texttop],
img[align=texttop], input[type=image][align=texttop], object[align=texttop] { /*
case-insensitive */
vertical-align: text-top;
}
applet[align=absmiddle], embed[align=absmiddle], iframe[align=absmiddle],
img[align=absmiddle], input[type=image][align=absmiddle], object[align=absmiddle],
applet[align=abscenter], embed[align=abscenter], iframe[align=abscenter],
img[align=abscenter], input[type=image][align=abscenter], object[align=abscenter] { /*
case-insensitive */
vertical-align: middle;
}
applet[align=bottom], embed[align=bottom], iframe[align=bottom],
img[align=bottom], input[type=image][align=bottom],
object[align=bottom] { /* case-insensitive */
vertical-align: bottom;
}
When an applet p665 , embed p205 , iframe p199 , img p186 , or object p208 element, or an input p303 element whose type p304
attribute is in the Image Button p321 state, has an align attribute whose value is an ASCII case-insensitive p33 match
for the string "center" or the string "middle", the user agent is expected to act as if the element's 'vertical-align'
property was set to a value that aligns the vertical middle of the element with the parent element's baseline.
The hspace attribute of applet p665 , embed p205 , iframe p199 , img p186 , or object p208 elements, and input p303 elements
with a type p304 attribute in the Image Button p321 state, maps to the dimension properties p638 'margin-left' and
'margin-right' on the element.
The vspace attribute of applet p665 , embed p205 , iframe p199 , img p186 , or object p208 elements, and input p303 elements
with a type p304 attribute in the Image Button p321 state, maps to the dimension properties p638 'margin-top' and
'margin-bottom' on the element.
When an img p186 element, object p208 element, or input p303 element with a type p304 attribute in the Image
Button p321 state is contained within a hyperlink p383 and has a border attribute whose value, when parsed using the
rules for parsing non-negative integers p35 , is found to be a number greater than zero, the user agent is expected
to use the parsed value for eight presentational hints p638 : four setting the parsed value as a pixel length for the
element's 'border-top-width', 'border-right-width', 'border-bottom-width', and 'border-left-width' properties, and
four setting the element's 'border-top-style', 'border-right-style', 'border-bottom-style', and 'border-left-style'
properties to the value 'solid'.
The width p271 and height p271 attributes on applet p665 , embed p205 , iframe p199 , img p186 , object p208 or video p213
elements, and input p303 elements with a type p304 attribute in the Image Button p321 state, map to the dimension
properties p638 'width' and 'height' on the element respectively.
650
12.3.4 Image maps
Shapes on an image map p268 are expected to act, for the purpose of the CSS cascade, as elements independent of
the original area p266 element that happen to match the same style rules but inherit from the img p186 or object p208
element.
For the purposes of the rendering, only the 'cursor' property is expected to have any effect on the shape.
Thus, for example, if an area p266 element has a style p86 attribute that sets the 'cursor' property to 'help',
then when the user designates that shape, the cursor would change to a Help cursor.
Similarly, if an area p266 element had a CSS rule that set its 'cursor' property to 'inherit' (or if no rule setting
the 'cursor' property matched the element at all), the shape's cursor would be inherited from the img p186 or
object p208 element of the image map p268 , not from the parent of the area p266 element.
12.3.5 Toolbars
When a menu p372 element's type p373 attribute is in the toolbar p373 state, the element is expected to be treated as a
replaced element with a height about two lines high and a width derived from the contents of the element.
The element is expected to have, by default, the appearance of a toolbar on the user agent's platform. It is
expected to contain the menu that is built p374 from the element.
12.4 Bindings
12.4.1 Introduction
A number of elements have their rendering defined in terms of the 'binding' property. [BECSS] p700
The CSS snippets below set the 'binding' property to a user-agent-defined value, represented below by keywords
like button. The rules then described for these bindings are only expected to apply if the element's 'binding'
property has not been overridden (e.g. by the author) to have another value.
Exactly how the bindings are implemented is not specified by this specification. User agents are encouraged to
make their bindings set the 'appearance' CSS property appropriately to achieve platform-native appearances for
widgets, and are expected to implement any relevant animations, etc, that are appropriate for the platform.
[CSSUI] p701
12.4.2 The button p332 element
@namespace url(http://www.w3.org/1999/xhtml);
button { binding: button; }
When the button binding applies to a button p332 element, the element is expected to render as an 'inline-block'
box rendered as a button whose contents are the contents of the element.
12.4.3 The details p367 element
@namespace url(http://www.w3.org/1999/xhtml);
details { binding: details; }
When the details binding applies to a details p367 element, the element is expected to render as a 'block' box with
its 'padding-left' property set to '40px' for left-to-right elements (LTR-specific p638 ) and with its 'padding-right'
property set to '40px' for right-to-left elements. The element's shadow tree is expected to take the element's first
child summary p370 element, if any, and place it in a first 'block' box container, and then take the element's
remaining descendants, if any, and place them in a second 'block' box container.
The first container is expected to contain at least one line box, and that line box is expected to contain a
disclosure widget (typically a triangle), horizontally positioned within the left padding of the details p367 element.
That widget is expected to allow the user to request that the details be shown or hidden.
The second container is expected to have its 'overflow' property set to 'hidden'. When the details p367 element
does not have an open p367 attribute, this second container is expected to be removed from the rendering.
651
12.4.4 The input p303 element as a text entry widget
@namespace url(http://www.w3.org/1999/xhtml);
input { binding: input-textfield; }
input[type=password] { binding: input-password; } /* case-insensitive */
/* later rules override this for other values of type="" */
When the input-textfield binding applies to an input p303 element whose type p304 attribute is in the Text p307 ,
Search p307 , Telephone p308 , URL p308 , or E-mail p309 state, the element is expected to render as an 'inline-block' box
rendered as a text field.
When the input-password binding applies, to an input p303 element whose type p304 attribute is in the Password p310
state, the element is expected to render as an 'inline-block' box rendered as a text field whose contents are
obscured.
If an input p303 element whose type p304 attribute is in one of the above states has a size p326 attribute, and parsing
that attribute's value using the rules for parsing non-negative integers p35 doesn't generate an error, then the user
agent is expected to use the attribute as a presentational hint p638 for the 'width' property on the element, with the
value obtained from applying the converting a character width to pixels p652 algorithm to the value of the attribute.
If an input p303 element whose type p304 attribute is in one of the above states does not have a size p326 attribute,
then the user agent is expected to act as if it had a user-agent-level style sheet rule setting the 'width' property on
the element to the value obtained from applying the converting a character width to pixels p652 algorithm to the
number 20.
The converting a character width to pixels algorithm returns (size-1)×avg + max, where size is the character
width to convert, avg is the average character width of the primary font for the element for which the algorithm is
being run, in pixels, and max is the maximum character width of that same font, also in pixels. (The element's
'letter-spacing' property does not affect the result.)
12.4.5 The input p303 element as domain-specific widgets
@namespace url(http://www.w3.org/1999/xhtml);
input[type=datetime] { binding: input-datetime; } /* case-insensitive */
input[type=date] { binding: input-date; } /* case-insensitive */
input[type=month] { binding: input-month; } /* case-insensitive */
input[type=week] { binding: input-week; } /* case-insensitive */
input[type=time] { binding: input-time; } /* case-insensitive */
input[type=datetime-local] { binding: input-datetime-local; } /* case-insensitive */
input[type=number] { binding: input-number; } /* case-insensitive */
When the input-datetime binding applies to an input p303 element whose type p304 attribute is in the Date and
Time p310 state, the element is expected to render as an 'inline-block' box depicting a Date and Time control.
When the input-date binding applies to an input p303 element whose type p304 attribute is in the Date p311 state, the
element is expected to render as an 'inline-block' box depicting a Date control.
When the input-month binding applies to an input p303 element whose type p304 attribute is in the Month p312 state,
the element is expected to render as an 'inline-block' box depicting a Month control.
When the input-week binding applies to an input p303 element whose type p304 attribute is in the Week p313 state, the
element is expected to render as an 'inline-block' box depicting a Week control.
When the input-time binding applies to an input p303 element whose type p304 attribute is in the Time p314 state, the
element is expected to render as an 'inline-block' box depicting a Time control.
When the input-datetime-local binding applies to an input p303 element whose type p304 attribute is in the Local
Date and Time p314 state, the element is expected to render as an 'inline-block' box depicting a Local Date and
Time control.
When the input-number binding applies to an input p303 element whose type p304 attribute is in the Number p315
state, the element is expected to render as an 'inline-block' box depicting a Number control.
These controls are all expected to be about one line high, and about as wide as necessary to show the widest
possible value.
652
12.4.6 The input p303 element as a range control
@namespace url(http://www.w3.org/1999/xhtml);
input[type=range] { binding: input-range; } /* case-insensitive */
When the input-range binding applies to an input p303 element whose type p304 attribute is in the Range p316 state,
the element is expected to render as an 'inline-block' box depicting a slider control.
When the control is wider than it is tall (or square), the control is expected to be a horizontal slider, with the lowest
value on the right if the 'direction' property on this element has a computed value of 'rtl', and on the left
otherwise. When the control is taller than it is wide, it is expected to be a vertical slider, with the lowest value on
the bottom.
Predefined suggested values (provided by the list p324 attribute) are expected to be shown as tick marks on the
slider, which the slider can snap to.
12.4.7 The input p303 element as a color well
@namespace url(http://www.w3.org/1999/xhtml);
input[type=color] { binding: input-color; } /* case-insensitive */
When the input-color binding applies to an input p303 element whose type p304 attribute is in the Color p318 state, the
element is expected to render as an 'inline-block' box depicting a color well, which, when activated, provides the
user with a color picker (e.g. a color wheel or color palette) from which the color can be changed.
Predefined suggested values (provided by the list p324 attribute) are expected to be shown in the color picker
interface, not on the color well itself.
12.4.8 The input p303 element as a check box and radio button widgets
@namespace url(http://www.w3.org/1999/xhtml);
input[type=checkbox] { binding: input-checkbox; } /* case-insensitive */
input[type=radio] { binding: input-radio; } /* case-insensitive */
When the input-checkbox binding applies to an input p303 element whose type p304 attribute is in the Checkbox p318
state, the element is expected to render as an 'inline-block' box containing a single check box control, with no
label.
When the input-radio binding applies to an input p303 element whose type p304 attribute is in the Radio Button p319
state, the element is expected to render as an 'inline-block' box containing a single radio button control, with no
label.
12.4.9 The input p303 element as a file upload control
@namespace url(http://www.w3.org/1999/xhtml);
input[type=file] { binding: input-file; } /* case-insensitive */
When the input-file binding applies to an input p303 element whose type p304 attribute is in the File Upload p320 state,
the element is expected to render as an 'inline-block' box containing a span of text giving the filename(s) of the
selected files p320 , if any, followed by a button that, when activated, provides the user with a file picker from which
the selection can be changed.
12.4.10 The input p303 element as a button
@namespace url(http://www.w3.org/1999/xhtml);
input[type=submit], input[type=reset], input[type=button] { /* case-insensitive */
binding: input-button;
}
653
When the input-button binding applies to an input p303 element whose type p304 attribute is in the Submit
Button p321 , Reset Button p323 , or Button p323 state, the element is expected to render as an 'inline-block' box
rendered as a button, about one line high, containing the contents of the element's value p306 attribute, if any, or
text derived from the element's type p304 attribute in a user-agent-defined (and probably locale-specific) fashion, if
not.
12.4.11 The marquee p666 element
@namespace url(http://www.w3.org/1999/xhtml);
marquee {
binding: marquee;
}
When the marquee binding applies to a marquee p666 element, while the element is turned on p666 , the element is
expected to render in an animated fashion according to its attributes as follows:
If the element's behavior p666 attribute is in the scroll p666 state
Slide the contents of the element in the direction described by the direction p666 attribute as defined below,
such that it begins off the start side of the marquee p666 , and ends flush with the inner end side.
For example, if the direction p666 attribute is left p666 (the default), then the contents would start such
that their left edge are off the side of the right edge of the marquee p666 's content area, and the
contents would then slide up to the point where the left edge of the contents are flush with the left
inner edge of the marquee p666 's content area.
Once the animation has ended, the user agent is expected to increment the marquee current loop index p667 .
If the element is still turned on p666 after this, then the user agent is expected to restart the animation.
If the element's behavior p666 attribute is in the slide p666 state
Slide the contents of the element in the direction described by the direction p666 attribute as defined below,
such that it begins off the start side of the marquee p666 , and ends off the end side of the marquee p666 .
For example, if the direction p666 attribute is left p666 (the default), then the contents would start such
that their left edge are off the side of the right edge of the marquee p666 's content area, and the
contents would then slide up to the point where the right edge of the contents are flush with the left
inner edge of the marquee p666 's content area.
Once the animation has ended, the user agent is expected to increment the marquee current loop index p667 .
If the element is still turned on p666 after this, then the user agent is expected to restart the animation.
If the element's behavior p666 attribute is in the alternate p666 state
When the marquee current loop index p667 is even (or zero), slide the contents of the element in the direction
described by the direction p666 attribute as defined below, such that it begins flush with the start side of the
marquee p666 , and ends flush with the end side of the marquee p666 .
When the marquee current loop index p667 is odd, slide the contents of the element in the opposite direction
than that described by the direction p666 attribute as defined below, such that it begins flush with the end
side of the marquee p666 , and ends flush with the start side of the marquee p666 .
For example, if the direction p666 attribute is left p666 (the default), then the contents would with their
right edge flush with the right inner edge of the marquee p666 's content area, and the contents would
then slide up to the point where the left edge of the contents are flush with the left inner edge of the
marquee p666 's content area.
Once the animation has ended, the user agent is expected to increment the marquee current loop index p667 .
If the element is still turned on p666 after this, then the user agent is expected to continue the animation.
The direction p666 attribute has the meanings described in the following table:
direction p666 attribute state Direction of animation Start edge End edge
p666
Opposite direction
← Right to left
Right
Left
→ Left to Right
right p666
→ Left to Right
Left
Right
← Right to left
up p666
↑ Up (Bottom to Top)
Bottom
Top
↓ Down (Top to Bottom)
down p667
↓ Down (Top to Bottom)
Top
Bottom
↑ Up (Bottom to Top)
left
In any case, the animation should proceed such that there is a delay given by the marquee scroll interval p667
between each frame, and such that the content moves at most the distance given by the marquee scroll
distance p667 with each frame.
654
When a marquee p666 element has a bgcolor attribute set, the value is expected to be parsed using the rules for
parsing a legacy color value p48 , and if that does not return an error, the user agent is expected to treat the
attribute as a presentational hint p638 setting the element's 'background-color' property to the resulting color.
The width and height attributes on a marquee p666 element map to the dimension properties p638 'width' and
'height' on the element respectively.
The intrinsic height of a marquee p666 element with its direction p666 attribute in the up p666 or down p667 states is 200
CSS pixels.
The vspace attribute of a marquee p666 element maps to the dimension properties p638 'margin-top' and 'marginbottom' on the element. The hspace attribute of a marquee p666 element maps to the dimension properties p638
'margin-left' and 'margin-right' on the element.
The 'overflow' property on the marquee p666 element is expected to be ignored; overflow is expected to always be
hidden.
12.4.12 The meter p349 element
@namespace url(http://www.w3.org/1999/xhtml);
meter {
binding: meter;
}
When the meter binding applies to a meter p349 element, the element is expected to render as an 'inline-block' box
with a 'height' of '1em' and a 'width' of '5em', a 'vertical-align' of '-0.2em', and with its contents depicting a gauge.
When the element is wider than it is tall (or square), the depiction is expected to be of a horizontal gauge, with the
minimum value on the right if the 'direction' property on this element has a computed value of 'rtl', and on the left
otherwise. When the element is taller than it is wide, it is expected to depict a vertical gauge, with the minimum
value on the bottom.
User agents are expected to use a presentation consistent with platform conventions for gauges, if any.
Note: Requirements for what must be depicted in the gauge are included in the definition of
the meter p349 element.
12.4.13 The progress p348 element
@namespace url(http://www.w3.org/1999/xhtml);
progress {
binding: progress;
}
When the progress binding applies to a progress p348 element, the element is expected to render as an 'inlineblock' box with a 'height' of '1em' and a 'width' of '10em', a 'vertical-align' of '-0.2em', and with its contents
depicting a horizontal progress bar, with the start on the right and the end on the left if the 'direction' property on
this element has a computed value of 'rtl', and with the start on the left and the end on the right otherwise.
User agents are expected to use a presentation consistent with platform conventions for progress bars. In
particular, user agents are expected to use different presentations for determinate and indeterminate progress
bars. User agents are also expected to vary the presentation based on the dimensions of the element.
For example, on some platforms for showing indeterminate progress there is an asynchronous progress
indicator with square dimensions, which could be used when the element is square, and an indeterminate
progress bar, which could be used when the element is wide.
Note: Requirements for how to determine if the progress bar is determinate or indeterminate,
and what progress a determinate progress bar is to show, are included in the definition of the
progress p348 element.
12.4.14 The select p334 element
@namespace url(http://www.w3.org/1999/xhtml);
655
select {
binding: select;
}
When the select binding applies to a select p334 element whose multiple p335 attribute is present, the element is
expected to render as a multi-select list box.
When the select binding applies to a select p334 element whose multiple p335 attribute is absent, and the element's
size p335 attribute specifies p35 a value greater than 1, the element is expected to render as a single-select list box.
When the element renders as a list box, it is expected to render as an 'inline-block' box whose 'height' is the
height necessary to contain as many rows for items as specified p35 by the element's size p335 attribute, or four
rows if the attribute is absent, and whose 'width' is the width of the select's labels p656 plus the width of a
scrollbar.
When the select binding applies to a select p334 element whose multiple p335 attribute is absent, and the element's
size p335 attribute is either absent or specifies p35 either no value (an error), or a value less than or equal to 1, the
element is expected to render as a one-line drop down box whose width is the width of the select's labels p656 .
In either case (list box or drop-down box), the element's items are expected to be the element's list of options p335 ,
with the element's optgroup p338 element children providing headers for groups of options where applicable.
The width of the select's labels is the wider of the width necessary to render the widest optgroup p338 , and the
width necessary to render the widest option p339 element in the element's list of options p335 (including its indent, if
any).
An optgroup p338 element is expected to be rendered by displaying the element's label p339 attribute.
An option p339 element is expected to be rendered by displaying the element's label p340 , indented under its
optgroup p338 element if it has one.
12.4.15 The textarea p341 element
@namespace url(http://www.w3.org/1999/xhtml);
textarea { binding: textarea; }
When the textarea binding applies to a textarea p341 element, the element is expected to render as an 'inlineblock' box rendered as a multiline text field.
If the element has a cols p342 attribute, and parsing that attribute's value using the rules for parsing non-negative
integers p35 doesn't generate an error, then the user agent is expected to use the attribute as a presentational
hint p638 for the 'width' property on the element, with the value being the textarea effective width p656 (as defined
below). Otherwise, the user agent is expected to act as if it had a user-agent-level style sheet rule setting the
'width' property on the element to the textarea effective width p656 .
The textarea effective width of a textarea p341 element is size×avg + sbw, where size is the element's
character width p342 , avg is the average character width of the primary font of the element, in CSS pixels, and sbw
is the width of a scroll bar, in CSS pixels. (The element's 'letter-spacing' property does not affect the result.)
If the element has a rows p343 attribute, and parsing that attribute's value using the rules for parsing non-negative
integers p35 doesn't generate an error, then the user agent is expected to use the attribute as a presentational
hint p638 for the 'height' property on the element, with the value being the textarea effective height p656 (as defined
below). Otherwise, the user agent is expected to act as if it had a user-agent-level style sheet rule setting the
'height' property on the element to the textarea effective height p656 .
The textarea effective height of a textarea p341 element is the height in CSS pixels of the number of lines
specified the element's character height p343 , plus the height of a scrollbar in CSS pixels.
For historical reasons, if the element has a wrap p343 attribute whose value is an ASCII case-insensitive p33 match for
the string "off", then the user agent is expected to not wrap the rendered value; otherwise, the value of the
control is expected to be wrapped to the width of the control.
12.4.16 The keygen p344 element
@namespace url(http://www.w3.org/1999/xhtml);
keygen { binding: keygen; }
656
When the keygen binding applies to a keygen p344 element, the element is expected to render as an 'inline-block'
box containing a user interface to configure the key pair to be generated.
12.4.17 The time p168 element
@namespace url(http://www.w3.org/1999/xhtml);
time:empty { binding: time; }
When the time binding applies to a time p168 element, the element is expected to render as if it contained text
conveying the date p170 (if known), time p170 (if known), and time-zone offset p170 (if known) represented by the
element, in the fashion most convenient for the user.
12.5 Frames and framesets
When an html p106 element's second child element is a frameset p668 element, the user agent is expected to render
the frameset p668 element as described below across the surface of the viewport, instead of applying the usual CSS
rendering rules.
When rendering a frameset p668 on a surface, the user agent is expected to use the following layout algorithm:
1.
The cols and rows variables are lists of zero or more pairs consisting of a number and a unit, the unit
being one of percentage, relative, and absolute.
Use the rules for parsing a list of dimensions p40 to parse the value of the element's cols attribute, if
there is one. Let cols be the result, or an empty list if there is no such attribute.
Use the rules for parsing a list of dimensions p40 to parse the value of the element's rows attribute, if
there is one. Let rows be the result, or an empty list if there is no such attribute.
2.
For any of the entries in cols or rows that have the number zero and the unit relative, change the entry's
number to one.
3.
If cols has no entries, then add a single entry consisting of the value 1 and the unit relative to cols.
If rows has no entries, then add a single entry consisting of the value 1 and the unit relative to rows.
4.
Invoke the algorithm defined below to convert a list of dimensions to a list of pixel values p658 using cols
as the input list, and the width of the surface that the frameset p668 is being rendered into, in CSS pixels,
as the input dimension. Let sized cols be the resulting list.
Invoke the algorithm defined below to convert a list of dimensions to a list of pixel values p658 using rows
as the input list, and the height of the surface that the frameset p668 is being rendered into, in CSS pixels,
as the input dimension. Let sized rows be the resulting list.
5.
Split the surface into a grid of w×h rectangles, where w is the number of entries in sized cols and h is
the number of entries in sized rows.
Size the columns so that each column in the grid is as many CSS pixels wide as the corresponding entry
in the sized cols list.
Size the rows so that each row in the grid is as many CSS pixels high as the corresponding entry in the
sized rows list.
6.
Let children be the list of frame p668 and frameset p668 elements that are children of the frameset p668
element for which the algorithm was invoked.
7.
For each row of the grid of rectangles created in the previous step, from top to bottom, run these
substeps:
1.
For each rectangle in the row, from left to right, run these substeps:
1.
If there are any elements left in children, take the first element in the list, and assign
it to the rectangle.
If this is a frameset p668 element, then recurse the entire frameset p668 layout
algorithm for that frameset p668 element, with the rectangle as the surface.
Otherwise, it is a frame p668 element; create a nested browsing context p439 sized to fit
the rectangle.
2.
If there are any elements left in children, remove the first element from children.
657
8.
If the frameset p668 element has a border p658 , draw an outer set of borders around the rectangles, using
the element's frame border color p658 .
For each rectangle, if there is an element assigned to that rectangle, and that element has a border p658 ,
draw an inner set of borders around that rectangle, using the element's frame border color p658 .
For each (visible) border that does not abut a rectangle that is assigned a frame p668 element with a
noresize attribute (including rectangles in further nested frameset p668 elements), the user agent is
expected to allow the user to move the border, resizing the rectangles within, keeping the proportions of
any nested frameset p668 grids.
A frameset p668 or frame p668 element has a border if the following algorithm returns true:
1.
If the element has a frameborder attribute whose value is not the empty string and whose
first character is either a U+0031 DIGIT ONE (1) character, a U+0079 LATIN SMALL LETTER Y
character (y), or a U+0059 LATIN CAPITAL LETTER Y character (Y), then return true.
2.
Otherwise, if the element has a frameborder attribute, return false.
3.
Otherwise, if the element has a parent element that is a frameset p668 element, then return
true if that element has a border p658 , and false if it does not.
4.
Otherwise, return true.
The frame border color of a frameset p668 or frame p668 element is the color obtained from the following
algorithm:
1.
If the element has a bordercolor attribute, and applying the rules for parsing a legacy color
value p48 to that attribute's value does not result in an error, then return the color so obtained.
2.
Otherwise, if the element has a parent element that is a frameset p668 element, then the frame
border color p658 of that element.
3.
Otherwise, return gray.
The algorithm to convert a list of dimensions to a list of pixel values consists of the following steps:
1.
Let input list be the list of numbers and units passed to the algorithm.
Let output list be a list of numbers the same length as input list, all zero.
Entries in output list correspond to the entries in input list that have the same position.
2.
Let input dimension be the size passed to the algorithm.
3.
Let count percentage be the number of entries in input list whose unit is percentage.
Let total percentage be the sum of all the numbers in input list whose unit is percentage.
Let count relative be the number of entries in input list whose unit is relative.
Let total relative be the sum of all the numbers in input list whose unit is relative.
Let count absolute be the number of entries in input list whose unit is absolute.
Let total absolute be the sum of all the numbers in input list whose unit is absolute.
Let remaining space be the value of input dimension.
4.
If total absolute is greater than remaining space, then for each entry in input list whose unit is absolute,
set the corresponding value in output list to the number of the entry in input list multiplied by remaining
space and divided by total absolute. Then, set remaining space to zero.
Otherwise, for each entry in input list whose unit is absolute, set the corresponding value in output list to
the number of the entry in input list. Then, decrement remaining space by total absolute.
5.
If total percentage multiplied by the input dimension and divided by 100 is greater than remaining
space, then for each entry in input list whose unit is percentage, set the corresponding value in output
list to the number of the entry in input list multiplied by remaining space and divided by total
percentage. Then, set remaining space to zero.
Otherwise, for each entry in input list whose unit is percentage, set the corresponding value in output
list to the number of the entry in input list multiplied by the input dimension and divided by 100. Then,
decrement remaining space by total percentage multiplied by the input dimension and divided by 100.
6.
658
For each entry in input list whose unit is relative, set the corresponding value in output list to the
number of the entry in input list multiplied by remaining space and divided by total relative.
7.
Return output list.
User agents working with integer values for frame widths (as opposed to user agents that can lay frames out with
subpixel accuracy) are expected to distribute the remainder first to the last entry whose unit is relative, then
equally (not proportionally) to each entry whose unit is percentage, then equally (not proportionally) to each entry
whose unit is absolute, and finally, failing all else, to the last entry.
12.6 Interactive media
12.6.1 Links, forms, and navigation
User agents are expected to allow the user to control aspects of hyperlink p383 activation and form submission p360 ,
such as which browsing context p439 is to be used for the subsequent navigation p459 .
User agents are expected to allow users to discover the destination of hyperlinks p383 and of forms p297 before
triggering their navigation p459 .
User agents are expected to inform the user of whether a hyperlink p383 includes hyperlink auditing p385 , and to let
them know at a minimum which domains will be contacted as part of such auditing.
User agents are expected to allow users to navigate p459 browsing contexts p439 to the resources indicated p51 by the
cite attributes on q p166 , blockquote p151 , section p133 , article p136 , ins p182 , and del p183 elements.
User agents are expected to surface hyperlinks p383 created by link p109 elements in their user interface.
Note: While link p109 elements that create hyperlinks p383 will match the ':link' or ':visited'
pseudo-classes, will react to clicks if visible, and so forth, this does not extend to any browser
interface constructs that expose those same links. Activating a link through the browser's
interface, rather than in the page itself, does not trigger click p31 events and the like.
12.6.2 The title p84 attribute
Given an element (e.g. the element designated by the mouse cursor), if the element, or one of its ancestors, has a
title p84 attribute, and the nearest such attribute has a value that is not the empty string, it is expected that the
user agent will expose the contents of that attribute as a tooltip.
User agents are encouraged to make it possible to view tooltips without the use of a pointing device, since not all
users are able to use pointing devices.
U+000A LINE FEED (LF) characters are expected to cause line breaks in the tooltip.
12.6.3 Editing hosts
The current text editing caret (the one at the caret position p518 in a focused editing host p518 ) is expected to act like
an inline replaced element with the vertical dimensions of the caret and with zero width for the purposes of the
CSS rendering model.
Note: This means that even an empty block can have the caret inside it, and that when the
caret is in such an element, it prevents margins from collapsing through the element.
12.7 Print media
User agents are expected to allow the user to request the opportunity to obtain a physical form (or a
representation of a physical form) of a Document p31 . For example, selecting the option to print a page or convert it
to PDF format.
When the user actually obtains a physical form p659 (or a representation of a physical form) of a Document p31 , the
user agent is expected to create a new rendering of the Document p31 for the print media.
659
13 Obsolete features
13.1 Obsolete but conforming features
Features listed in this section will trigger warnings in conformance checkers.
Authors should not specify an http-equiv p115 attribute in the Content Language p115 state on a meta p112 element.
The lang p85 attribute should be used instead.
Authors should not specify a border p664 attribute on an img p186 element. If the attribute is present, its value must
be the string "0". CSS should be used instead.
Authors should not specify a language p663 attribute on a script p122 element. If the attribute is present, its value
must be an ASCII case-insensitive p33 match for the string "JavaScript" and either the type p123 attribute must be
omitted or its value must be an ASCII case-insensitive p33 match for the string "text/javascript". The attribute
should be entirely omitted instead (with the value "JavaScript", it has no effect), or replaced with use of the
type p123 attribute.
Authors should not specify the name p662 attribute on a p160 elements. If the attribute is present, its value must not be
the empty string and must neither be equal to the value of any of the IDs p84 in the element's home subtree p27
other than the element's own ID p84 , if any, nor be equal to the value of any of the other name p662 attributes on a p160
elements in the element's home subtree p27 . If this attribute is present and the element has an ID p84 , then the
attribute's value must be equal to the element's ID p84 . In earlier versions of the language, this attribute was
intended as a way to specify possible targets for fragment identifiers in URLs p51 . The id p84 attribute should be
used instead.
Note: In the HTML syntax p547 , specifying a DOCTYPE p547 that is an obsolete permitted
DOCTYPE p548 will also trigger a warning.
Note: The summary p275 attribute, defined in the table p271 section, will also trigger a warning.
13.1.1 Warnings for obsolete but conforming features
To ease the transition from HTML4 Transitional documents to the language defined in this specification, and to
discourage certain features that are only allowed in very few circumstances, conformance checkers are required to
warn the user when the following features are used in a document. These are generally old obsolete features that
have no effect, and are allowed only to distinguish between likely mistakes (regular conformance errors) and mere
vestigial markup or unusual and discouraged practices (these warnings).
The following features must be categorized as described above:
•
The presence of an obsolete permitted DOCTYPE p548 in an HTML document p71 .
•
The presence of a meta p112 element with an http-equiv p115 attribute in the Content Language p115 state.
•
The presence of a border p664 attribute on an img p186 element if its value is the string "0".
•
The presence of a language p663 attribute on a script p122 element if its value is an ASCII caseinsensitive p33 match for the string "JavaScript" and if there is no type p123 attribute or there is and its
value is an ASCII case-insensitive p33 match for the string "text/javascript".
•
The presence of a name p662 attribute on an a p160 element, if its value is not the empty string.
•
The presence of a summary p275 attribute on a table p271 element.
Conformance checkers must distinguish between pages that have no conformance errors and have none of these
obsolete features, and pages that have no conformance errors but do have some of these obsolete features.
For example, a validator could report some pages as "Valid HTML" and others as "Valid HTML with
warnings".
13.2 Non-conforming features
Elements in the following list are entirely obsolete, and must not be used by authors:
applet p665
Use embed p205 or object p208 instead.
660
acronym
Use abbr p167 instead.
bgsound
Use audio p216 instead.
dir
Use ul p153 instead.
frame p668
frameset p668
noframes
Either use iframe p199 and CSS instead, or use server-side includes to generate complete pages with the
various invariant parts merged in.
isindex
Use an explicit form p297 and text field p307 combination instead.
listing
xmp
Use pre p150 and code p171 instead.
nextid
Use GUIDs instead.
noembed
Use object p208 instead of embed p205 when fallback is necessary.
plaintext
Use the "text/plain" MIME type p26 instead.
rb
Providing the ruby base directly inside the ruby p177 element is sufficient; the rb p661 element is unnecessary.
Omit it altogether.
basefont
big
blink
center
font
marquee p666
multicol
nobr
s
spacer
strike
tt
u
Use appropriate elements and/or CSS instead.
For the s p661 and strike p661 elements, if they are marking up a removal from the element, consider using the
del p183 element instead.
Where the tt p661 element would have been used for marking up keyboard input, consider the kbd p173
element; for variables, consider the var p172 element; for computer code, consider the code p171 element; and
for computer output, consider the samp p172 element.
Similarly, if the u p661 element is being used to indicate emphasis, consider using the em p162 element; if it is
being used for marking up keywords, consider the b p175 element; and if it is being used for highlighting text
for reference purposes, consider the mark p176 element.
See also the text-level semantics usage summary p182 for more suggestions with examples.
The following attributes are obsolete (though the elements are still part of the language), and must not be used by
authors:
661
charset on a p160 elements
charset on link p109 elements
Use an HTTP Content-Type header on the linked resource instead.
coords on a p160 elements
shape on a p160 elements
Use area p266 instead of a p160 for image maps.
methods on a p160 elements
methods on link p109 elements
Use the HTTP OPTIONS feature instead.
name on a p160 elements (except as noted in the previous section)
name on embed p205 elements
name on img p186 elements
name on option p339 elements
Use the id p84 attribute instead.
rev on a p160 elements
rev on link p109 elements
Use the rel p384 attribute instead, with an opposite term. (For example, instead of rev="made", use
rel="author".)
urn on a p160 elements
urn on link p109 elements
Specify the preferred persistent identifier using the href p383 attribute instead.
nohref on area p266 elements
Omitting the href p383 attribute is sufficient; the nohref p662 attribute is unnecessary. Omit it altogether.
profile on head p106 elements
When used for declaring which meta p112 terms are used in the document, unnecessary; omit it altogether,
and register the names p114 .
When used for triggering specific user agent behaviors: use a link p109 element instead.
version on html p106 elements
Unnecessary. Omit it altogether.
usemap on input p303 elements
Use img p186 instead of input p303 for image maps.
longdesc on iframe p199 elements
longdesc on img p186 elements
Use a regular a p160 element to link to the description.
target on link p109 elements
Unnecessary. Omit it altogether.
scheme on meta p112 elements
Use only one scheme per field, or make the scheme declaration part of the value.
archive on object p208 elements
classid on object p208 elements
code on object p208 elements
codebase on object p208 elements
codetype on object p208 elements
Use the data p209 and type p209 attributes to invoke plugins p27 . To set parameters with these names in
particular, the param p213 element can be used.
declare on object p208 elements
Repeat the object p208 element completely each time the resource is to be reused.
standby on object p208 elements
Optimize the linked resource so that it loads quickly or, at least, incrementally.
662
type on param p213 elements
valuetype on param p213 elements
Use the name p213 and value p213 attributes without declaring value types.
language on script p122 elements (except as noted in the previous section)
Use the type p123 attribute instead.
event on script p122 elements
for on script p122 elements
Use DOM Events mechanisms to register event listeners. [DOMEVENTS] p701
datapagesize on table p271 elements
Unnecessary. Omit it altogether.
abbr on td p282 and th p283 elements
Use text that begins in an unambiguous and terse manner, and include any more elaborate text after that.
axis on td p282 and th p283 elements
Use the scope p283 attribute on the relevant th p283 .
datasrc on a p160 , applet p665 , button p332 , div p159 , frame p668 , iframe p199 , img p186 , input p303 , label p301 , legend p301 ,
marquee p666 , object p208 , option p339 , select p334 , span p180 , table p271 , and textarea p341 elements
datafld on a p160 , applet p665 , button p332 , div p159 , fieldset p300 , frame p668 , iframe p199 , img p186 , input p303 ,
label p301 , legend p301 , marquee p666 , object p208 , param p213 , select p334 , span p180 , and textarea p341 elements
dataformatas on button p332 , div p159 , input p303 , label p301 , legend p301 , marquee p666 , object p208 , option p339 ,
select p334 , span p180 , table p271
Use script and a mechanism such as XMLHttpRequest to populate the page dynamically. [XHR] p705
663
alink on body p131 elements
bgcolor on body p131 elements
link on body p131 elements
marginbottom on body p131 elements
marginheight on body p131 elements
marginleft on body p131 elements
marginright on body p131 elements
marginheight on body p131 elements
marginwidth on body p131 elements
text on body p131 elements
vlink on body p131 elements
clear on br p181 elements
align on caption p277 elements
align on col p279 elements
char on col p279 elements
charoff on col p279 elements
valign on col p279 elements
width on col p279 elements
align on div p159 elements
compact on dl p155 elements
align on embed p205 elements
hspace on embed p205 elements
vspace on embed p205 elements
align on hr p149 elements
color on hr p149 elements
noshade on hr p149 elements
size on hr p149 elements
width on hr p149 elements
align on h1 p139 —h6 p139 elements
align on iframe p199 elements
allowtransparency on iframe p199 elements
frameborder on iframe p199 elements
hspace on iframe p199 elements
marginheight on iframe p199 elements
marginwidth on iframe p199 elements
scrolling on iframe p199 elements
vspace on iframe p199 elements
align on input p303 elements
hspace on input p303 elements
vspace on input p303 elements
align on img p186 elements
border on img p186 elements (except as noted in the previous section)
hspace on img p186 elements
vspace on img p186 elements
align on legend p301 elements
type on li p154 elements
compact on menu p372 elements
align on object p208 elements
border on object p208 elements
hspace on object p208 elements
vspace on object p208 elements
compact on ol p152 elements
type on ol p152 elements
align on p p148 elements
width on pre p150 elements
align on table p271 elements
bgcolor on table p271 elements
border on table p271 elements
664
cellpadding on table p271 elements
cellspacing on table p271 elements
frame on table p271 elements
rules on table p271 elements
width on table p271 elements
align on tbody p279 , thead p280 , and tfoot p280 elements
char on tbody p279 , thead p280 , and tfoot p280 elements
charoff on tbody p279 , thead p280 , and tfoot p280 elements
valign on tbody p279 , thead p280 , and tfoot p280 elements
align on td p282 and th p283 elements
bgcolor on td p282 and th p283 elements
char on td p282 and th p283 elements
charoff on td p282 and th p283 elements
height on td p282 and th p283 elements
nowrap on td p282 and th p283 elements
valign on td p282 and th p283 elements
width on td p282 and th p283 elements
align on tr p281 elements
bgcolor on tr p281 elements
char on tr p281 elements
charoff on tr p281 elements
valign on tr p281 elements
compact on ul p153 elements
type on ul p153 elements
background on body p131 , table p271 , thead p280 , tbody p279 , tfoot p280 , tr p281 , td p282 , and th p283 elements
Use CSS instead.
13.3 Requirements for implementations
13.3.1 The applet element
The applet p665 element is a Java-specific variant of the embed p205 element. The applet p665 element is now
obsoleted so that all extension frameworks (Java, .NET, Flash, etc) are handled in a consistent manner.
When the element is still in the stack of open elements p563 of an HTML parser p554 or XML parser p635 , and when the
element is not in a Document p27 , and when the element's document is not fully active p440 , and when the element's
Document p31 's browsing context p439 had its sandboxed plugins browsing context flag p202 when that Document p31 was
created, and when the element's Document p31 was parsed from a resource whose sniffed type p57 as determined
during navigation p459 is text/html-sandboxed p679 , and when the element has an ancestor media element p219 , and
when the element has an ancestor object p208 element that is not showing its fallback content p92 , and when no
Java Language runtime plugin p27 is available, and when one is available but it is disabled, the element
represents p638 its contents.
Otherwise, the user agent should instantiate a Java Language runtime plugin p27 , and should pass the names and
values of all the attributes on the element, in the order they were added to the element, with the attributes added
by the parser being ordered in source order, and then a parameter named "PARAM" whose value is null, and then
all the names and values of parameters p213 given by param p213 elements that are children of the applet p665
element, in tree order p27 , to the plugin p27 used. If the plugin p27 supports a scriptable interface, the
HTMLAppletElement p665 object representing the element should expose that interface. The applet p665 element
represents p638 the plugin p27 .
Note: The applet p665 element is unaffected by the CSS 'display' property. The Java Language
runtime is instantiated even if the element is hidden with a 'display:none' CSS style.
The applet p665 element must implement the HTMLAppletElement p665 interface.
interface HTMLAppletElement : HTMLElement {
attribute DOMString align;
attribute DOMString alt;
attribute DOMString archive;
attribute DOMString code;
attribute DOMString codeBase;
attribute DOMString height;
665
attribute
attribute
attribute
attribute
attribute
unsigned long hspace;
DOMString name;
DOMString _object; // the underscore is not part of the identifier
unsigned long vspace;
DOMString width;
};
The align, alt, archive, code, height, hspace, name, object, vspace, and width IDL attributes must reflect p57
the respective content attributes of the same name.
The codeBase IDL attribute must reflect p57 the codebase content attribute.
13.3.2 The marquee element
The marquee p666 element is a presentational element that animates content. CSS transitions and animations are a
more appropriate mechanism.
The task source p490 for tasks mentioned in this section is the DOM manipulation task source p491 .
The marquee p666 element must implement the HTMLMarqueeElement p666 interface.
interface HTMLMarqueeElement : HTMLElement {
attribute DOMString behavior;
attribute DOMString bgColor;
attribute DOMString direction;
attribute DOMString height;
attribute unsigned long hspace;
attribute long loop;
attribute unsigned long scrollAmount;
attribute unsigned long scrollDelay;
attribute DOMString trueSpeed;
attribute unsigned long vspace;
attribute DOMString width;
attribute Function onbounce;
attribute Function onfinish;
attribute Function onstart;
void start();
void stop();
};
A marquee p666 element can be turned on or turned off. When it is created, it is turned on p666 .
When the start() method is called, the marquee p666 element must be turned on p666 .
When the stop() method is called, the marquee p666 element must be turned off p666 .
When a marquee p666 element is created, the user agent must queue a task p490 to fire a simple event p496 named
start at the element.
The behavior content attribute on marquee p666 elements is an enumerated attribute p34 with the following
keywords (all non-conforming):
Keyword
State
scroll
scroll
slide
slide
alternate alternate
The missing value default is the scroll p666 state.
The direction content attribute on marquee p666 elements is an enumerated attribute p34 with the following
keywords (all non-conforming):
Keyword State
666
left
left
right
right
up
up
Keyword State
down
down
The missing value default is the left p666 state.
The truespeed content attribute on marquee p666 elements is an enumerated attribute p34 with the following
keywords (all non-conforming):
Keyword State
true
true
false
false
The missing value default is the false p667 state.
A marquee p666 element has a marquee scroll interval, which is obtained as follows:
1.
If the element has a scrolldelay attribute, and parsing its value using the rules for parsing nonnegative integers p35 does not return an error, then let delay be the parsed value. Otherwise, let delay be
85.
2.
If the element does not have a truespeed p667 attribute, or if it does but that attribute is in the false p667
state, and the delay value is less than 60, then let delay be 60 instead.
3.
The marquee scroll interval p667 is delay, interpreted in milliseconds.
A marquee p666 element has a marquee scroll distance, which, if the element has a scrollamount attribute, and
parsing its value using the rules for parsing non-negative integers p35 does not return an error, is the parsed value
interpreted in CSS pixels, and otherwise is 6 CSS pixels.
A marquee p666 element has a marquee loop count, which, if the element has a loop attribute, and parsing its
value using the rules for parsing integers p35 does not return an error or a number less than 1, is the parsed value,
and otherwise is −1.
The loop IDL attribute, on getting, must return the element's marquee loop count p667 ; and on setting, if the new
value is different than the element's marquee loop count p667 and either greater than zero or equal to −1, must set
the element's loop content attribute (adding it if necessary) to the valid integer p35 that represents the new value.
(Other values are ignored.)
A marquee p666 element also has a marquee current loop index, which is zero when the element is created.
The rendering layer will occasionally increment the marquee current loop index, which must cause the
following steps to be run:
1.
If the marquee loop count p667 is −1, then abort these steps.
2.
Increment the marquee current loop index p667 by one.
3.
If the marquee current loop index p667 is now equal to or greater than the element's marquee loop
count p667 , turn off p666 the marquee p666 element and queue a task p490 to fire a simple event p496 named
finish at the marquee p666 element.
Otherwise, if the behavior p666 attribute is in the alternate p666 state, then queue a task p490 to fire a simple
event p496 named bounce at the marquee p666 element.
Otherwise, queue a task p490 to fire a simple event p496 named start at the marquee p666 element.
The following are the event handlers p492 (and their corresponding event handler event types p493 ) that must be
supported, as content and IDL attributes, by marquee p666 elements:
Event handler p492 Event handler event type p493
onbounce
bounce
onfinish
finish
onstart
start
The behavior, direction, height, hspace, vspace, and width IDL attributes must reflect p57 the respective
content attributes of the same name.
The bgColor IDL attribute must reflect p57 the bgcolor content attribute.
667
The scrollAmount IDL attribute must reflect p57 the scrollamount content attribute. The default value is 6.
The scrollDelay IDL attribute must reflect p57 the scrolldelay content attribute. The default value is 85.
The trueSpeed IDL attribute must reflect p57 the truespeed p667 content attribute.
13.3.3 Frames
The frameset element acts as the body element p76 in documents that use frames.
The frameset p668 element must implement the HTMLFrameSetElement p668 interface.
interface HTMLFrameSetElement : HTMLElement {
attribute DOMString cols;
attribute DOMString rows;
attribute Function onafterprint;
attribute Function onbeforeprint;
attribute Function onbeforeunload;
attribute Function onblur;
attribute Function onerror;
attribute Function onfocus;
attribute Function onhashchange;
attribute Function onload;
attribute Function onmessage;
attribute Function onoffline;
attribute Function ononline;
attribute Function onpagehide;
attribute Function onpageshow;
attribute Function onpopstate;
attribute Function onredo;
attribute Function onresize;
attribute Function onstorage;
attribute Function onundo;
attribute Function onunload;
};
The cols and rows IDL attributes of the frameset p668 element must reflect p57 the respective content attributes of
the same name.
The frameset p668 element must support the following event handler content attributes p492 exposing the event
handlers p492 of the Window p443 object:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
onafterprint p495
onbeforeprint p495
onbeforeunload p495
onblur p495
onerror p495
onfocus p495
onhashchange p495
onload p495
onmessage p495
onoffline p495
ononline p495
onpagehide p495
onpageshow p495
onpopstate p495
onredo p495
onresize p495
onstorage p496
onundo p496
onunload p496
The DOM interface also exposes event handler IDL attributes p492 that mirror those on the Window p443 element.
The onblur p495 , onerror p495 , onfocus p495 , and onload p495 event handler IDL attributes p492 of the Window p443 object,
exposed on the frameset p668 element, shadow the generic event handler IDL attributes p492 with the same names
normally supported by HTML elements p26 .
The frame element defines a nested browsing context p439 similar to the iframe p199 element, but rendered within a
frameset p668 element.
668
When the browsing context is created, if a src attribute is present, the user agent must resolve p51 the value of
that attribute, relative to the element, and if that is successful, must then navigate p459 the element's browsing
context to the resulting absolute URL p52 , with replacement enabled p466 , and with the frame p668 element's
document's browsing context p439 as the source browsing context p459 .
Whenever the src attribute is set, the user agent must resolve p51 the value of that attribute, relative to the
element, and if that is successful, the nested browsing context p439 must be navigated p459 to the resulting absolute
URL p52 , with the frame p668 element's document's browsing context p439 as the source browsing context p459 .
When the browsing context is created, if a name attribute is present, the browsing context name p442 must be set to
the value of this attribute; otherwise, the browsing context name p442 must be set to the empty string.
Whenever the name attribute is set, the nested browsing context p439 's name p442 must be changed to the new value.
If the attribute is removed, the browsing context name p442 must be set to the empty string.
When content loads in a frame p668 , after any load events are fired within the content itself, the user agent must
queue a task p490 to fire a simple event p496 named load at the frame p668 element. When content fails to load (e.g.
due to a network error), then the user agent must queue a task p490 to fire a simple event p496 named error at the
element instead.
The task source p490 for the tasks p489 above is the DOM manipulation task source p491 .
When there is an active parser p75 in the frame p668 , and when anything in the frame p668 is delaying the load
event p619 of the frame p668 's browsing context p439 's active document p439 , the frame p668 must delay the load event p619
of its document.
The frame p668 element must implement the HTMLFrameElement p669 interface.
interface HTMLFrameElement : HTMLElement {
attribute DOMString frameBorder;
attribute DOMString longDesc;
attribute DOMString marginHeight;
attribute DOMString marginWidth;
attribute DOMString name;
attribute boolean noResize;
attribute DOMString scrolling;
attribute DOMString src;
readonly attribute Document contentDocument;
};
The name, scrolling, and src IDL attributes of the frame p668 element must reflect p57 the respective content
attributes of the same name.
The frameBorder IDL attribute of the frame p668 element must reflect p57 the element's frameborder content
attribute.
The longDesc IDL attribute of the frame p668 element must reflect p57 the element's longdesc content attribute.
The marginHeight IDL attribute of the frame p668 element must reflect p57 the element's marginheight content
attribute.
The marginWidth IDL attribute of the frame p668 element must reflect p57 the element's marginwidth content
attribute.
The noResize IDL attribute of the frame p668 element must reflect p57 the element's noresize content attribute.
The contentDocument IDL attribute of the frame p668 element must return the Document p31 object of the active
document p439 of the frame p668 element's nested browsing context p439 .
13.3.4 Other elements, attributes and APIs
User agents must treat acronym p661 elements in a manner equivalent to abbr p167 elements.
[Supplemental]
interface HTMLAnchorElement {
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
coords;
charset;
name;
rev;
669
attribute DOMString shape;
};
The coords, charset, name, rev, and shape IDL attributes of the a p160 element must reflect p57 the respective
content attributes of the same name.
[Supplemental]
interface HTMLAreaElement {
attribute boolean noHref;
};
The noHref IDL attribute of the area p266 element must reflect p57 the element's nohref p662 content attribute.
The basefont p661 element must implement the HTMLBaseFontElement p670 interface.
interface HTMLBaseFontElement : HTMLElement {
attribute DOMString color;
attribute DOMString face;
attribute long size;
};
The color, face, and size IDL attributes of the basefont p661 element must reflect p57 the respective content
attributes of the same name.
[Supplemental]
interface HTMLBodyElement {
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
};
text;
bgColor;
background;
link;
vLink;
aLink;
The text IDL attribute of the body p131 element must reflect p57 the element's text p664 content attribute.
The bgColor IDL attribute of the body p131 element must reflect p57 the element's bgcolor p664 content attribute.
The background IDL attribute of the body p131 element must reflect p57 the element's background p665 content
attribute. (The background p665 content is not defined to contain a URL p51 , despite rules regarding its handling in
the rendering section above.)
The link IDL attribute of the body p131 element must reflect p57 the element's link p664 content attribute.
The aLink IDL attribute of the body p131 element must reflect p57 the element's alink p664 content attribute.
The vLink IDL attribute of the body p131 element must reflect p57 the element's vlink p664 content attribute.
[Supplemental]
interface HTMLBRElement {
attribute DOMString clear;
};
The clear IDL attribute of the br p181 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLTableCaptionElement {
attribute DOMString align;
};
The align IDL attribute of the caption p277 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLTableColElement {
670
attribute
attribute
attribute
attribute
attribute
DOMString
DOMString
DOMString
DOMString
DOMString
align;
ch;
chOff;
vAlign;
width;
};
The align and width IDL attributes of the col p279 element must reflect p57 the respective content attributes of the
same name.
The ch IDL attribute of the col p279 element must reflect p57 the element's char p664 content attribute.
The chOff IDL attribute of the col p279 element must reflect p57 the element's charoff p664 content attribute.
The vAlign IDL attribute of the col p279 element must reflect p57 the element's valign p664 content attribute.
User agents must treat dir p661 elements in a manner equivalent to ul p153 elements.
The dir p661 element must implement the HTMLDirectoryElement p671 interface.
interface HTMLDirectoryElement : HTMLElement {
attribute boolean compact;
};
The compact IDL attribute of the dir p661 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLDivElement {
attribute DOMString align;
};
The align IDL attribute of the div p159 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLDListElement {
attribute boolean compact;
};
The compact IDL attribute of the dl p155 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLEmbedElement {
attribute DOMString align;
attribute DOMString name;
};
The name and align IDL attributes of the embed p205 element must reflect p57 the respective content attributes of the
same name.
The font p661 element must implement the HTMLFontElement p671 interface.
interface HTMLFontElement : HTMLElement {
attribute DOMString color;
attribute DOMString face;
attribute DOMString size;
};
The color, face, and size IDL attributes of the font p661 element must reflect p57 the respective content attributes
of the same name.
[Supplemental]
interface HTMLHeadingElement {
attribute DOMString align;
};
671
The align IDL attribute of the h1 p139 –h6 p139 elements must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLHeadElement {
attribute DOMString profile;
};
User agents should ignore the profile p662 content attribute on head p106 elements.
When the attribute would be used as a list of URLs p51 identifying metadata profiles, the user agent should instead
always assume that all known profiles apply to all pages, and should therefore apply the conventions of all known
metadata profiles to the document, ignoring the value of the attribute.
When the attribute's value would be handled as a list of URLs p51 to be dereferenced, the user agent must use the
following steps:
1.
Split on spaces p49 the value of the profile p662 attribute.
2.
Resolve p51 each resulting token relative to the head p106 element.
3.
For each token that is successfully resolved, fetch p55 the resulting absolute URL p52 and apply the
appropriate processing.
The profile IDL attribute of the head p106 element must reflect p57 the content attribute of the same name, as if the
attribute's value was just a string. (In other words, the value is not resolved p51 in any way on getting.)
[Supplemental]
interface HTMLHRElement {
attribute DOMString align;
attribute DOMString color;
attribute boolean noShade;
attribute DOMString size;
attribute DOMString width;
};
The align, color, size, and width IDL attributes of the hr p149 element must reflect p57 the respective content
attributes of the same name.
The noShade IDL attribute of the hr p149 element must reflect p57 the element's noshade content attribute.
[Supplemental]
interface HTMLHtmlElement {
attribute DOMString version;
};
The version IDL attribute of the html p106 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLIFrameElement {
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
attribute DOMString
};
align;
frameBorder;
longDesc;
marginHeight;
marginWidth;
scrolling;
The align and scrolling IDL attributes of the iframe p199 element must reflect p57 the respective content
attributes of the same name.
The frameBorder IDL attribute of the iframe p199 element must reflect p57 the element's frameborder p664 content
attribute.
The longDesc IDL attribute of the iframe p199 element must reflect p57 the element's longdesc p662 content attribute.
The marginHeight IDL attribute of the iframe p199 element must reflect p57 the element's marginheight p664 content
attribute.
672
The marginWidth IDL attribute of the iframe p199 element must reflect p57 the element's marginwidth p664 content
attribute.
[Supplemental]
interface HTMLImageElement {
attribute DOMString name;
attribute DOMString align;
attribute DOMString border;
attribute unsigned long hspace;
attribute DOMString longDesc;
attribute unsigned long vspace;
};
The name, align, border, hspace, and vspace IDL attributes of the img p186 element must reflect p57 the respective
content attributes of the same name.
The longDesc IDL attribute of the img p186 element must reflect p57 the element's longdesc p662 content attribute.
[Supplemental]
interface HTMLInputElement {
attribute DOMString align;
attribute DOMString useMap;
};
The align IDL attribute of the input p303 element must reflect p57 the content attribute of the same name.
The useMap IDL attribute of the input p303 element must reflect p57 the element's usemap p662 content attribute.
[Supplemental]
interface HTMLLegendElement {
attribute DOMString align;
};
The align IDL attribute of the legend p301 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLLIElement {
attribute DOMString type;
};
The type IDL attribute of the li p154 element must reflect p57 the content attribute of the same name.
[Supplemental]
interface HTMLLinkElement {
attribute DOMString charset;
attribute DOMString rev;
attribute DOMString target;
};
The charset, rev, and target IDL attributes of the link p109 element must reflect p57 the respective content
attributes of the same name.
User agents must treat listing p661 elements in a manner equivalent to pre p150 elements.
[Supplemental]
interface HTMLMenuElement {
attribute boolean compact;
};
The compact IDL attribute of the menu p372 element must reflect p57 the content attribute of the same name.
673
[Supplemental]
interface HTMLMetaElement {
attribute DOMString scheme;
};
User agents may treat the scheme p662 content attribute on the meta p112 element as an extension of the element's
name p113 content attribute when processing a meta p112 element with a name p113 attribute whose value is one that
the user agent recognizes as supporting the scheme p662 attribute.
User agents are encouraged to ignore the scheme p662 attribute and instead process the value given to the
metadata name as if it had been specified for each expected value of the scheme p662 attribute.
For example, if the user agent acts on meta p112 elements with name p113 attributes having the value
"eGMS.subject.keyword", and knows that the scheme p662 attribute is used with this metadata name, then it
could take the scheme p662 attribute into account, acting as if it was an extension of the name p113 attribute.
Thus the following two meta p112 elements could be treated as two elements giving values for two different
metadata names, one consisting of a combination of "eGMS.subject.keyword" and "LGCL", and the other
consisting of a combination of "eGMS.subject.keyword" and "ORLY":
Intended usage:
Common
Restrictions on usage:
No restrictions apply.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers used with text/html p678 resources refer to the indicated part of the document p465 .
14.2 text/html-sandboxed
This registration is for community review and will be submitted to the IESG for review, approval, and registration
with IANA.
Type name:
text
Subtype name:
html-sandboxed
Required parameters:
No required parameters
Optional parameters:
Same as for text/html p678
Encoding considerations:
Same as for text/html p678
Security considerations:
The purpose of the text/html-sandboxed p679 MIME type is to provide a way for content providers to indicate
that they want the file to be interpreted in a manner that does not give the file's contents access to the rest
of the site. This is achieved by assigning the Document p31 objects generated from resources labeled as text/
html-sandboxed p679 unique origins.
To avoid having legacy user agents treating resources labeled as text/html-sandboxed p679 as regular text/
html p678 files, authors should avoid using the .html or .htm extensions for resources labeled as text/htmlsandboxed p679 .
Beyond this, the type is identical to text/html p678 , and the same considerations apply.
Interoperability considerations:
Same as for text/html p678
Published specification:
This document is the relevant specification. Labeling a resource with the text/html-sandboxed p679 type
asserts that the resource is an HTML document p71 using the HTML syntax p547 .
Applications that use this media type:
Same as for text/html p678
Additional information:
Magic number(s):
Documents labeled as text/html-sandboxed p679 are heuristically indistinguishable from those labeled
as text/html p678 .
File extension(s):
"sandboxed"
Macintosh file type code(s):
TEXT
Person & email address to contact for further information:
Ian Hickson
Intended usage:
Common
679
Restrictions on usage:
No restrictions apply.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers used with text/html-sandboxed p679 resources refer to the indicated part of the document p465 .
14.3 application/xhtml+xml
This registration is for community review and will be submitted to the IESG for review, approval, and registration
with IANA.
Type name:
application
Subtype name:
xhtml+xml
Required parameters:
Same as for application/xml [RFC3023] p703
Optional parameters:
Same as for application/xml [RFC3023] p703
Encoding considerations:
Same as for application/xml [RFC3023] p703
Security considerations:
Same as for application/xml [RFC3023] p703
Interoperability considerations:
Same as for application/xml [RFC3023] p703
Published specification:
Labeling a resource with the application/xhtml+xml p680 type asserts that the resource is an XML document
that likely has a root element from the HTML namespace p70 . As such, the relevant specifications are the XML
specification, the Namespaces in XML specification, and this specification. [XML] p705 [XMLNS] p705
Applications that use this media type:
Same as for application/xml [RFC3023] p703
Additional information:
Magic number(s):
Same as for application/xml [RFC3023] p703
File extension(s):
"xhtml" and "xht" are sometimes used as extensions for XML resources that have a root element from
the HTML namespace p70 .
Macintosh file type code(s):
TEXT
Person & email address to contact for further information:
Ian Hickson
Intended usage:
Common
Restrictions on usage:
No restrictions apply.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers used with application/xhtml+xml p680 resources have the same semantics as with any XML
MIME type p27 . [RFC3023] p703
680
14.4 text/cache-manifest
This registration is for community review and will be submitted to the IESG for review, approval, and registration
with IANA.
Type name:
text
Subtype name:
cache-manifest
Required parameters:
No parameters
Optional parameters:
No parameters
Encoding considerations:
Always UTF-8.
Security considerations:
Cache manifests themselves pose no immediate risk unless sensitive information is included within the
manifest. Implementations, however, are required to follow specific rules when populating a cache based on
a cache manifest, to ensure that certain origin-based restrictions are honored. Failure to correctly implement
these rules can result in information leakage, cross-site scripting attacks, and the like.
Interoperability considerations:
Rules for processing both conforming and non-conforming content are defined in this specification.
Published specification:
This document is the relevant specification.
Applications that use this media type:
Web browsers.
Additional information:
Magic number(s):
Cache manifests begin with the string "CACHE MANIFEST", followed by either a U+0020 SPACE
character, a U+0009 CHARACTER TABULATION (tab) character, a U+000A LINE FEED (LF) character, or
a U+000D CARRIAGE RETURN (CR) character.
File extension(s):
"manifest"
Macintosh file type code(s):
No specific Macintosh file type codes are recommended for this type.
Person & email address to contact for further information:
Ian Hickson
Intended usage:
Common
Restrictions on usage:
No restrictions apply.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers have no meaning with text/cache-manifest p681 resources.
14.5 text/ping
This registration is for community review and will be submitted to the IESG for review, approval, and registration
with IANA.
Type name:
text
Subtype name:
ping
681
Required parameters:
No parameters
Optional parameters:
No parameters
Encoding considerations:
Not applicable.
Security considerations:
If used exclusively in the fashion described in the context of hyperlink auditing p385 , this type introduces no
new security concerns.
Interoperability considerations:
Rules applicable to this type are defined in this specification.
Published specification:
This document is the relevant specification.
Applications that use this media type:
Web browsers.
Additional information:
Magic number(s):
text/ping p681 resources always consist of the four bytes 0x50 0x49 0x4E 0x47 (ASCII 'PING').
File extension(s):
No specific file extension is recommended for this type.
Macintosh file type code(s):
No specific Macintosh file type codes are recommended for this type.
Person & email address to contact for further information:
Ian Hickson
Intended usage:
Common
Restrictions on usage:
Only intended for use with HTTP POST requests generated as part of a Web browser's processing of the
ping p384 attribute.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers have no meaning with text/ping p681 resources.
14.6 application/microdata+json
This registration is for community review and will be submitted to the IESG for review, approval, and registration
with IANA.
Type name:
application
Subtype name:
microdata+json
Required parameters:
Same as for application/json [JSON] p701
Optional parameters:
Same as for application/json [JSON] p701
Encoding considerations:
Always UTF-8.
Security considerations:
Same as for application/json [JSON] p701
Interoperability considerations:
Same as for application/json [JSON] p701
682
Published specification:
Labeling a resource with the application/microdata+json p682 type asserts that the resource is a JSON text
that consists of an object with a single entry called "items" consisting of an array of entries, each of which
consists of an object with two entries, one called "type" whose value is an array of strings, and one called
"properties" whose value is an object whose entries each have a value consisting of an array of either
objects or strings, the objects being of the same form as the objects in the aforementioned "items" entry. As
such, the relevant specifications are the JSON specification and this specification. [JSON] p701
Applications that use this media type:
Same as for application/json [JSON] p701
Additional information:
Magic number(s):
Same as for application/json [JSON] p701
File extension(s):
Same as for application/json [JSON] p701
Macintosh file type code(s):
Same as for application/json [JSON] p701
Person & email address to contact for further information:
Ian Hickson
Intended usage:
Common
Restrictions on usage:
No restrictions apply.
Author:
Ian Hickson
Change controller:
W3C and WHATWG
Fragment identifiers used with application/microdata+json p682 resources have the same semantics as when
used with application/json. [JSON] p701
14.7 Ping-From
This section describes a header field for registration in the Permanent Message Header Field Registry.
[RFC3864] p703
Header field name
Ping-From
Applicable protocol
http
Status
standard
Author/Change controller
W3C and WHATWG
Specification document(s)
This document is the relevant specification.
Related information
None.
14.8 Ping-To
This section describes a header field for registration in the Permanent Message Header Field Registry.
[RFC3864] p703
Header field name
Ping-To
Applicable protocol
http
683
Status
standard
Author/Change controller
W3C and WHATWG
Specification document(s)
This document is the relevant specification.
Related information
None.
684
Index
The following sections only cover conforming elements and features.
Elements
This section is non-normative.
List of elements
Element
p160
Description
Categories
p91
Parents
p91
Children
p93
Attributes
p82
Interface
p383
globals ; href
; HTMLAnchorElement p161
target p384 ; ping p384 ;
rel p384 ; media p384 ;
hreflang p384 ;
type p384
Hyperlink
flow ;
phrasing p91 *;
interactive p92
phrasing
abbr p167
Abbreviation
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
address p143
Contact
information
for a page or
section
flow p91 ;
formatBlock
candidate p536
flow p91
flow p91 *
globals p82
HTMLElement p81
area p266
Hyperlink or
dead area on
an image
map
flow p91 ;
phrasing p91
phrasing p91 *
empty
globals p82 ; alt p266 ;
HTMLAreaElement p266
coords p267 ;
shape p267 ; href p383 ;
target p384 ; ping p384 ;
rel p384 ; media p384 ;
hreflang p384 ;
type p384
article p136
Selfcontained
syndicatable
or reusable
composition
flow p91 ;
sectioning p91 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82
HTMLElement p81
aside p137
Sidebar for
tangentially
related
content
flow p91 ;
sectioning p91 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82
HTMLElement p81
audio p216
Audio player
flow p91 ;
phrasing p91 ;
embedded p92 ;
interactive p92
phrasing p91
source p217 *;
transparent p93 *
globals p82 ; src p220 ;
preload p227 ;
autoplay p231 ;
loop p229 ;
controls p235
HTMLAudioElement p216
b p175
Keywords
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
base p108
Base URL and metadata p90
default target
browsing
context p439
for
hyperlinks p384
and forms p356
head p106
empty
globals p82 ; href p108 ;
target p109
HTMLBaseElement p108
bdo p180
Text
directionality
formatting
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
blockquote p151 A section
quoted from
another
source
flow p91 ;
sectioning
root p144 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82 ; cite p151
HTMLQuoteElement p151
body p131
sectioning
root p144
html p106
flow p91
globals p82 ;
HTMLBodyElement p132
onafterprint p495 ;
onbeforeprint p495 ;
onbeforeunload p495 ;
onblur p495 ;
onerror p495 ;
onfocus p495 ;
onhashchange p495 ;
onload p495 ;
onmessage p495 ;
onoffline p495 ;
ononline p495 ;
onpagehide p495 ;
onpageshow p495 ;
onpopstate p495 ;
onredo p495 ;
onresize p495 ;
a
Document
body
transparent
*
685
Element
Description
Categories
Parents
Children
Attributes
Interface
onstorage p496 ;
onundo p496 ;
onunload p496
br p181
Line break,
e.g. in poem
or postal
address
button p332
Button control flow p91 ;
phrasing p91
phrasing p91 ;
interactive p92 ;
listed p297 ;
labelable p297 ;
submittable p297 ;
formassociated p297
canvas p238
Scriptable
bitmap
canvas
flow p91 ;
phrasing p91 ;
embedded p92
caption p277
Table caption
none
cite
686
p165
flow p91 ;
phrasing p91
p91
Title of a work flow ;
phrasing p91
phrasing p91
empty
globals p82
Phrasing
content p91 *
globals p82 ;
HTMLButtonElement p333
autofocus p354 ;
disabled p354 ;
form p353 ;
formaction p355 ;
formenctype p356 ;
formmethod p355 ;
formnovalidate p356 ;
formtarget p356 ;
name p354 ; type p333 ;
value p334
phrasing p91
transparent p93
globals p82 ;
width p239 ;
height p239
HTMLCanvasElement p238
table p271
flow p91 *
globals p82
HTMLTableCaptionElement p277
phrasing
p91
phrasing
p91
globals
HTMLBRElement p181
p82
HTMLElement p81
code p171
Computer
code
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
col p279
Table column
none
colgroup p278
empty
globals p82 ; span p279
HTMLTableColElement p278
colgroup p278
Group of
columns in a
table
none
table p271
col p279
globals p82 ; span p278
HTMLTableColElement p278
command p371
Menu
command
metadata p90 ;
flow p91 ;
phrasing p91
head p106 ;
phrasing p91
empty
globals p82 ; type p371 ;
label p371 ; icon p371 ;
disabled p371 ;
checked p372 ;
radiogroup p372
HTMLCommandElement p371
datalist p338
Container for
options for
combo box
control p324
flow p91 ;
phrasing p91
phrasing p91
phrasing p91 ;
option p339
globals p82
HTMLDataListElement p338
dd p157
Content for
none
corresponding
dt p157
element(s)
dl p155
flow p91
globals p82
HTMLElement p81
del p183
A removal
from the
document
flow p91 ;
phrasing p91 *
phrasing p91
transparent p93
globals p82 ; cite p184 ;
datetime p184
HTMLModElement p184
details p367
Disclosure
control for
hiding details
flow p91 ;
sectioning
root p144 ;
interactive p92
flow p91
summary p370 *;
flow p91
globals p82 ; open p367
HTMLDetailsElement p367
dfn p167
Defining
instance
flow p91 ;
phrasing p91
phrasing p91
phrasing p91 *
globals p82
HTMLElement p81
div p159
Generic flow
container
flow p91 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82
HTMLDivElement p160
dl p155
Association
flow p91
list consisting
of zero or
more namevalue groups
flow p91
dt p157 *; dd p157 *
globals p82
HTMLDListElement p155
dt p157
Legend for
none
corresponding
dd p157
element(s)
dl p155
varies*
globals p82
HTMLElement p81
em p162
Stress
emphasis
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
embed p205
Plugin p27
flow p91 ;
phrasing p91 ;
embedded p92 ;
interactive p92
phrasing p91
empty
globals p82 ; src p206 ;
type p206 ; width p271 ;
height p271 ; any*
HTMLEmbedElement p206
fieldset p300
Group of form flow p91 ;
controls
sectioning
root p144 ;
flow p91
legend p301 *;
flow p91
globals p82 ;
disabled p300 ;
form p353 ; name p354
HTMLFieldSetElement p300
Element
Description
Categories
Parents
Children
Attributes
Interface
listed p297 ; formassociated p297
figcaption p159 Caption for
figure p158
none
figure p158
phrasing p91
globals p82
HTMLElement p81
figure p158
Figure with
optional
caption
flow p91 ;
sectioning
root p144
flow p91
figcaption p159 *; globals p82
flow p91
HTMLElement p81
footer p142
Footer for a
page or
section
flow p91 ;
formatBlock
candidate p536
flow p91
flow p91 *
globals p82
HTMLElement p81
form p297
Usersubmittable
form
flow p91
flow p91
flow p91 *
globals p82 ; accept- HTMLFormElement p297
charset p298 ;
action p355 ;
autocomplete p298 ;
enctype p356 ;
method p355 ; name p298 ;
novalidate p356 ;
target p356
h1 p139 , h2 p139 ,
h3 p139 , h4 p139 ,
h5 p139 , h6 p139
Section
heading
flow p91 ;
heading p91 ;
formatBlock
candidate p536
hgroup p140 ;
flow p91
phrasing p91
globals p82
HTMLHeadingElement p139
head p106
Container for
document
metadata
none
html p106
metadata
content p90 *
globals p82
HTMLHeadElement p107
header p140
Introductory
or
navigational
aids for a
page or
section
flow p91 ;
formatBlock
candidate p536
flow p91
flow p91 *
globals p82
HTMLElement p81
hgroup p140
heading
group
flow p91 ;
heading p91 ;
formatBlock
candidate p536
flow p91
One or more
h1 p139 , h2 p139 ,
h3 p139 , h4 p139 ,
h5 p139 , and/or
h6 p139
globals p82
HTMLElement p81
hr p149
Thematic
break
flow p91
flow p91
empty
globals p82
HTMLHRElement p149
html p106
Root element
none
none*
head p106 *;
body p131 *
globals p82 ;
manifest p106
HTMLHtmlElement p106
i p174
Alternate
voice
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
iframe p199
Nested
browsing
context p439
flow p91 ;
phrasing p91 ;
embedded p92 ;
interactive p92
phrasing p91
text*
globals p82 ; src p200 ;
HTMLIFrameElement p200
srcdoc p200 ; name p202 ;
sandbox p202 ;
seamless p204 ;
width p271 ;
height p271
img p186
Image
flow p91 ;
phrasing p91 ;
embedded p92 ;
interactive p92 *
phrasing p91
empty
globals p82 ; alt p186 ;
HTMLImageElement p186
src p186 ; usemap p268 ;
ismap p189 ; width p271 ;
height p271
input p303
Form control
flow p91 ;
phrasing p91
phrasing p91 ;
interactive p92 *;
listed p297 ;
labelable p297 ;
submittable p297 ;
resettable p297 ;
formassociated p297
empty
globals p82 ;
HTMLInputElement p303
accept p320 ; alt p322 ;
autocomplete p324 ;
autofocus p354 ;
checked p306 ;
disabled p354 ;
form p353 ;
formaction p355 ;
formenctype p356 ;
formmethod p355 ;
formnovalidate p356 ;
formtarget p356 ;
height p271 ; list p324 ;
max p328 ;
maxlength p327 ;
min p328 ;
multiple p327 ;
name p354 ;
pattern p328 ;
placeholder p329 ;
readonly p325 ;
required p326 ;
size p326 ; src p321 ;
687
Element
Description
Categories
Parents
Children
Attributes
Interface
step p329 ; type p304 ;
value p306 ; width p271
688
ins p182
An addition to flow p91 ;
the document phrasing p91 *
phrasing p91
transparent p93
globals p82 ; cite p184 ;
datetime p184
HTMLModElement p184
kbd p173
User input
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
keygen p344
Cryptographic
key-pair
generator
form control
flow p91 ;
phrasing p91
phrasing p91 ;
interactive p92 ;
listed p297 ;
labelable p297 ;
submittable p297 ;
resettable p297 ;
formassociated p297
empty
globals p82 ;
autofocus p354 ;
challenge p344 ;
disabled p354 ;
form p353 ;
keytype p344 ;
name p354
HTMLKeygenElement p344
label p301
Caption for a
form control
flow p91 ;
phrasing p91 ;
interactive p92 ;
formassociated p297
phrasing p91
phrasing p91 *
globals p82 ; form p353 ;
for p302
HTMLLabelElement p302
legend p301
Caption for
fieldset p300
none
fieldset p300
phrasing p91
globals p82
HTMLLegendElement p301
li p154
List item
none
ol p152 ; ul p153 ;
menu p372
flow p91
globals p82 ;
value p154 *
HTMLLIElement p154
link p109
Link
metadata
metadata p90 ;
flow p91 *;
phrasing p91 *
empty
head p106 ;
noscript p129 *;
phrasing p91 *
globals p82 ; href p109 ;
rel p110 ; media p111 ;
hreflang p111 ;
type p111 ; sizes p389
HTMLLinkElement p109
map p265
Image
map p268
flow p91 ;
phrasing p91 *
phrasing p91
transparent p93 ;
area p266 *
globals p82 ; name p265
HTMLMapElement p265
mark p176
Highlight
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
menu p372
Menu of
commands
flow p91 ;
interactive p92 *
flow p91
li p154 *; flow p91
globals p82 ; type p373 ;
label p373
HTMLMenuElement p373
meta p112
Text
metadata
metadata p90 ;
flow p91 *;
phrasing p91 *
empty
head p106 ;
noscript p129 *;
phrasing p91 *
globals p82 ; name p113 ;
http-equiv p115 ;
content p113 ;
charset p113
HTMLMetaElement p113
meter p349
Gauge
flow p91 ;
phrasing p91 ;
labelable p297 ;
formassociated p297
phrasing p91
phrasing p91 *
globals p82 ;
value p350 ; min p350 ;
max p350 ; low p350 ;
high p350 ;
optimum p350 ;
form p353
HTMLMeterElement p350
nav p134
Section with
navigational
links
flow p91 ;
sectioning p91 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82
HTMLElement p81
noscript p129
Fallback
content for
script
metadata p90 ;
flow p91 ;
phrasing p91
head p106 *;
phrasing p91 *
varies*
globals p82
HTMLElement p81
object p208
Image,
flow p91 ;
phrasing p91
p91
nested
phrasing ;
browsing
embedded p92 ;
p439
context
, or interactive p92 *;
plugin p27
listed p297 ;
submittable p297 ;
formassociated p297
param p213 *;
transparent p93
globals p82 ; data p209 ; HTMLObjectElement p208
type p209 ; name p209 ;
usemap p268 ; form p353 ;
width p271 ;
height p271
ol p152
Ordered list
flow p91
flow p91
li p154
globals p82 ;
reversed p152 ;
start p153
HTMLOListElement p152
optgroup p338
Group of
options in a
list box
none
select p334
option p339
globals p82 ;
disabled p339 ;
label p339
HTMLOptGroupElement p338
option p339
Option in a
list box or
combo box
control
none
select p334 ;
datalist p338 ;
optgroup p338
text p91
globals p82 ;
disabled p340 ;
label p340 ;
selected p340 ;
value p340
HTMLOptionElement p340
output p346
Calculated
output value
flow p91 ;
phrasing p91 ;
listed p297 ;
labelable p297 ;
phrasing p91
phrasing p91
globals p82 ; for p347 ;
form p353 ; name p354
HTMLOutputElement p346
Element
Description
Categories
Parents
Children
Attributes
Interface
resettable p297 ;
formassociated p297
p p148
Paragraph
flow p91 ;
formatBlock
candidate p536
flow p91
phrasing p91
globals p82
HTMLParagraphElement p148
param p213
Parameter for none
object p208
object p208
empty
globals p82 ; name p213 ;
value p213
HTMLParamElement p213
pre p150
Block of
preformatted
text
flow p91 ;
formatBlock
candidate p536
flow p91
phrasing p91
globals p82
HTMLPreElement p150
progress p348
Progress bar
flow p91 ;
phrasing p91 ;
labelable p297 ;
formassociated p297
phrasing p91
phrasing p91 *
globals p82 ;
value p348 ; max p348 ;
form p353
HTMLProgressElement p348
q p166
Quotation
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82 ; cite p166
HTMLQuoteElement p151
rp p179
Parenthesis
for ruby
annotation
text
none
ruby p177
phrasing p91
globals p82
HTMLElement p81
rt p179
Ruby
annotation
text
none
ruby p177
phrasing p91
globals p82
HTMLElement p81
ruby p177
Ruby
annotation(s)
flow p91 ;
phrasing p91
phrasing p91
phrasing p91 ;
rt p179 element;
rp p179 element*
globals p82
HTMLElement p81
samp p172
Computer
output
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
script p122
Embedded
script
metadata p90 ;
flow p91 ;
phrasing p91
head p106 ;
phrasing p91
script, data, or
script
documentation*
globals p82 ; src p123 ;
HTMLScriptElement p123
async p123 ; defer p123 ;
type p123 ;
charset p123
section p133
Generic
document or
application
section
flow p91 ;
sectioning p91 ;
formatBlock
candidate p536
flow p91
flow p91
globals p82
HTMLElement p81
select p334
List box
control
flow p91 ;
phrasing p91
phrasing p91 ;
interactive p92 ;
listed p297 ;
labelable p297 ;
submittable p297 ;
resettable p297 ;
formassociated p297
option p339 ,
optgroup p338
globals p82 ;
autofocus p354 ;
disabled p354 ;
form p353 ;
multiple p335 ;
name p354 ; size p335
HTMLSelectElement p335
small p164
Side
comment
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
source p217
Media source
for video p213
or audio p216
none
video p213 ;
audio p216
empty
globals p82 ; src p217 ;
type p217 ; media p218
HTMLSourceElement p217
span p180
Generic
phrasing
container
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLSpanElement p180
strong p163
Importance
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
style p119
Embedded
styling
information
metadata p90 ;
flow p91
varies*
head p106 ;
noscript p129 *;
flow p91 *
globals p82 ;
media p120 ; type p120 ;
scoped p120
HTMLStyleElement p119
sub p174
Subscript
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
summary p370
Caption for
details p367
none
details p367
phrasing p91
globals p82
HTMLElement p81
sup p174
Superscript
flow p91 ;
phrasing p91
phrasing p91
phrasing p91
globals p82
HTMLElement p81
table p271
Table
flow p91
flow p91
caption p277 *;
colgroup p278 *;
thead p280 *;
tbody p279 *;
tfoot p280 *;
tr p281 *
globals p82 ;
summary p275
HTMLTableElement p272
689
Element
Description
Categories
Parents
Children
Attributes
Interface
tbody p279
Group of rows none
in a table
table p271
tr p281
globals p82
HTMLTableSectionElement p279
td p282
Table cell
sectioning
root p144
tr p281
flow p91
globals p82 ;
colspan p284 ;
rowspan p284 ;
headers p284
HTMLTableDataCellElement p282
textarea p341
Multiline text
field
flow p91 ;
phrasing p91
phrasing p91 ;
interactive p92 ;
listed p297 ;
labelable p297 ;
submittable p297 ;
resettable p297 ;
formassociated p297
text p91
globals p82 ;
autofocus p354 ;
cols p342 ;
disabled p354 ;
form p353 ;
maxlength p343 ;
name p354 ;
placeholder p343 ;
readonly p342 ;
required p343 ;
rows p343 ; wrap p343
HTMLTextAreaElement p342
tfoot p280
Group of
none
footer rows in
a table
table p271
tr p281
globals p82
HTMLTableSectionElement p279
th p283
Table header
cell
none
tr p281
phrasing p91
globals p82 ;
colspan p284 ;
rowspan p284 ;
headers p284 ;
scope p283
HTMLTableHeaderCellElement p283
thead p280
Group of
heading rows
in a table
none
table p271
tr p281
globals p82
HTMLTableSectionElement p279
time p168
Date and/or
time
flow p91 ;
phrasing p91
phrasing p91
phrasing p91 *
globals p82 ;
datetime p169 ;
pubdate p169
HTMLTimeElement p169
title p107
Document
title
metadata p90
head p106
text p91
globals p82
HTMLTitleElement p107
tr p281
Table row
none
table p271 ;
thead p280 ;
tbody p279 ;
tfoot p280
th p283 *; td p282
globals p82
HTMLTableRowElement p281
ul p153
List
flow p91
flow p91
li p154
globals p82
HTMLUListElement p153
p172
p91
p91
p91
p82
HTMLElement p81
Variable
flow ;
phrasing p91
phrasing
video p213
Video player
flow p91 ;
phrasing p91 ;
embedded p92 ;
interactive p92
phrasing p91
source p217 *;
transparent p93 *
globals p82 ; src p220 ;
poster p214 ;
preload p227 ;
autoplay p231 ;
loop p229 ;
controls p235 ;
width p271 ;
height p271
HTMLVideoElement p214
wbr p181
Line breaking
opportunity
flow p91 ;
phrasing p91
phrasing p91
empty
globals p82
HTMLElement p81
var
phrasing
globals
An asterisk (*) in a cell indicates that the actual rules are more complicated than indicated in the table above.
Element content categories
This section is non-normative.
List of element content categories
Category
690
Elements
Elements with exceptions
Metadata
content p90
base p108 ; command p371 ; link p109 ; meta p112 ; noscript p129 ; script p122 ; style p119 ;
title p107
—
Flow
content p91
a p160 ; abbr p167 ; address p143 ; article p136 ; aside p137 ; audio p216 ; b p175 ; bdo p180 ;
blockquote p151 ; br p181 ; button p332 ; canvas p238 ; cite p165 ; code p171 ; command p371 ;
datalist p338 ; del p183 ; details p367 ; dfn p167 ; div p159 ; dl p155 ; em p162 ; embed p205 ;
fieldset p300 ; figure p158 ; footer p142 ; form p297 ; h1 p139 ; h2 p139 ; h3 p139 ; h4 p139 ; h5 p139 ;
h6 p139 ; header p140 ; hgroup p140 ; hr p149 ; i p174 ; iframe p199 ; img p186 ; input p303 ; ins p182 ;
kbd p173 ; keygen p344 ; label p301 ; map p265 ; mark p176 ; math p270 ; menu p372 ; meter p349 ;
nav p134 ; noscript p129 ; object p208 ; ol p152 ; output p346 ; p p148 ; pre p150 ; progress p348 ;
q p166 ; ruby p177 ; samp p172 ; script p122 ; section p133 ; select p334 ; small p164 ; span p180 ;
strong p163 ; sub p174 ; sup p174 ; svg p271 ; table p271 ; textarea p341 ; time p168 ; ul p153 ;
var p172 ; video p213 ; wbr p181 ; Text p91
area p266 (if it is a descendant of a
map p265 element); link p109 (if the
itemprop p405 attribute is present);
meta p112 (if the itemprop p405 attribute
is present); style p119 (if the
scoped p120 attribute is present)
Sectioning
content p91
article p136 ; aside p137 ; nav p134 ; section p133
—
Category
Elements
Elements with exceptions
Heading
content p91
h1 p139 ; h2 p139 ; h3 p139 ; h4 p139 ; h5 p139 ; h6 p139 ; hgroup p140
—
Phrasing
content p91
abbr p167 ; audio p216 ; b p175 ; bdo p180 ; br p181 ; button p332 ; canvas p238 ; cite p165 ; code p171 ;
command p371 ; datalist p338 ; dfn p167 ; em p162 ; embed p205 ; i p174 ; iframe p199 ; img p186 ;
input p303 ; kbd p173 ; keygen p344 ; label p301 ; mark p176 ; math p270 ; meter p349 ;
noscript p129 ; object p208 ; output p346 ; progress p348 ; q p166 ; ruby p177 ; samp p172 ;
script p122 ; select p334 ; small p164 ; span p180 ; strong p163 ; sub p174 ; sup p174 ; svg p271 ;
textarea p341 ; time p168 ; var p172 ; video p213 ; wbr p181 ; Text p91
a p160 (if it contains only phrasing
content p91 ); area p266 (if it is a
descendant of a map p265 element);
del p183 (if it contains only phrasing
content p91 ); ins p182 (if it contains
only phrasing content p91 ); link p109 (if
the itemprop p405 attribute is
present); map p265 (if it contains only
phrasing content p91 ); meta p112 (if the
itemprop p405 attribute is present)
Embedded
content p92
audio p216 canvas p238 embed p205 iframe p199 img p186 math p270 object p208 svg p271
video p213
—
Interactive
content p92
a p160 ; button p332 ; details p367 ; embed p205 ; iframe p199 ; keygen p344 ; label p301 ;
select p334 ; textarea p341 ;
audio p216 (if the controls p235
attribute is present); img p186 (if the
usemap p268 attribute is present);
input p303 (if the type p304 attribute is
not in the Hidden p307 state); menu p372
(if the type p373 attribute is in the
toolbar p373 state); object p208 (if the
usemap p268 attribute is present);
video p213 (if the controls p235
attribute is present)
Sectioning
roots p144
blockquote p151 ; body p131 ; details p367 ; fieldset p300 ; figure p158 ; td p282
—
Formassociated
elements p297
button p332 ; fieldset p300 ; input p303 ; keygen p344 ; label p301 ; meter p349 ; object p208 ;
output p346 ; progress p348 ; select p334 ; textarea p341
—
Listed
elements p297
button p332 ; fieldset p300 ; input p303 ; keygen p344 ; object p208 ; output p346 ; select p334 ; —
textarea p341
Labelable
elements p297
button p332 ; input p303 ; keygen p344 ; meter p349 ; output p346 ; progress p348 ; select p334 ;
textarea p341
—
Submittable
elements p297
button p332 ; input p303 ; keygen p344 ; object p208 ; select p334 ; textarea p341
—
Resettable
elements p297
input p303 ; keygen p344 ; output p346 ; select p334 ; textarea p341
—
formatBlock section p133 ; nav p134 ; article p136 ; aside p137 ; h1 p139 ; h2 p139 ; h3 p139 ; h4 p139 ; h5 p139 ;
candidates p536 h6 p139 ; hgroup p140 ; header p140 ; footer p142 ; address p143 ; p p148 ; pre p150 ;
blockquote p151 ; div p159
—
Attributes
This section is non-normative.
List of attributes (excluding event handler content attributes)
Attribute
Element(s)
Description
Value
Hint for expected file type in file
upload controls p320
Set of comma-separated tokens p50 *
consisting of valid MIME types with no
parameters p26 or audio/*, video/*, or
image/*
form p298
Character encodings to use for
form submission p360
Ordered set of unique space-separated
tokens p49 consisting of preferred MIME
names p28 of ASCII-compatible character
encodings p28 *
accesskey
HTML elements p512
Keyboard shortcut to activate or
focus element
Ordered set of unique space-separated
tokens p49 consisting of one Unicode
code point in length
action
form p355
URL p51 to use for form
submission p360
Valid URL p51
alt
area p266 ; img p186 ; input p322
Replacement text for use when
images are not available
Text*
async
script p123
Execute script asynchronously
Boolean attribute p34
Prevent the user agent from
providing autocompletions for the
form control(s)
"on"; "off"
accept
input
accept-charset
p320
p298
p324
autocomplete
form
autofocus
button p354 ; input p354 ; keygen p354 ;
select p354 ; textarea p354
Automatically focus the form
control when the page is loaded
Boolean attribute p34
autoplay
audio p231 ; video p231
Hint that the media resource p219
can be started automatically when
the page is loaded
Boolean attribute p34
; input
691
Attribute
Element(s)
Value
keygen p344
String to package with the
generated and signed public key
Text
charset
meta p113
Character encoding declaration p118
Preferred MIME name p28 of an encoding*
charset
script p123
Character encoding of the external Preferred MIME name p28 of an encoding*
script resource
checked
command p372 ; input p306
Whether the command or control is Boolean attribute p34
checked
cite
blockquote p151 ; del p184 ; ins p184 ; q p166
Link to the source of the quotation
or more information about the edit
Valid URL p51
class
HTML elements p86
Classes to which the element
belongs
Unordered set of unique spaceseparated tokens p49
cols
textarea p342
Maximum number of characters
per line
Valid non-negative integer p35 greater
than zero
colspan
td p284 ; th p284
Number of columns that the cell is
to span
Valid non-negative integer p35 greater
than zero
content
meta p113
Value of the element
Text*
Whether the element is
editable p518
"true"; "false"
contenteditable HTML elements
p518
contextmenu
HTML elements p375
The element's context menu
ID*
controls
audio p235 ; video p235
Show user agent controls
Boolean attribute p34
coords
area p267
Coordinates for the shape to be
created in an image map p268
Valid list of integers p38 *
data
object p209
Address of the resource
Valid non-empty URL p51
Time and date of the change
Valid global date and time string p44
Value of the element
Valid date or time string p46 *
Defer script execution
Boolean attribute p34
datetime
datetime
del
p184
time
; ins
p184
p169
p123
defer
script
dir
HTML elements p86
The text directionality p86 of the
element
"ltr"; "rtl"
disabled
button p354 ; command p371 ; fieldset p300 ;
input p354 ; keygen p354 ; optgroup p339 ;
option p340 ; select p354 ; textarea p354
Whether the form control is
disabled
Boolean attribute p34
draggable
HTML elements p531
Whether the element is draggable
"true"; "false"
enctype
form p356
Form data set encoding type to use "application/x-www-formfor form submission p360
urlencoded p356 "; "multipart/formdata p356 "; "text/plain p356 "
for
label p302
Associate the label with form
control
ID*
for
output p347
Specifies controls from which the
output was calculated
Unordered set of unique spaceseparated tokens p49 consisting of IDs*
form
button p353 ;
keygen p353 ;
object p353 ;
select p353 ;
Associates the control with a
form p297 element
ID*
formaction
button p355 ; input p355
URL p51 to use for form
submission p360
Valid URL p51
formenctype
button p356 ; input p356
Form data set encoding type to use "application/x-www-formfor form submission p360
urlencoded p356 "; "multipart/formdata p356 "; "text/plain p356 "
formmethod
button p355 ; input p355
HTTP method to use for form
submission p360
"GET"; "POST"; "PUT"; "DELETE"
formnovalidate
button p356 ; input p356
Bypass form control validation for
form submission p360
Boolean attribute p34
formtarget
button p356 ; input p356
Browsing context p439 for form
submission p360
Valid browsing context name or
keyword p442
headers
td p284 ; th p284
The header cells for this cell
Unordered set of unique spaceseparated tokens p49 consisting of IDs*
height
canvas p239 ; embed p271 ; iframe p271 ;
img p271 ; input p271 ; object p271 ;
video p271
Vertical dimension
Valid non-negative integer p35
hidden
HTML elements p508
Whether the element is relevant
Boolean attribute p34
high
meter p350
Low limit of high range
Valid floating point number p36 *
href
a p383 ; area p383
Address of the hyperlink p383
href
href
692
Description
challenge
link
p109
base
p108
p384
fieldset p353 ; input p353 ;
label p353 ; meter p353 ;
output p353 ; progress p353 ;
textarea p353
Address of the hyperlink
Document base URL
p384
p111
p383
p52
Valid URL p51
Valid non-empty URL p51
Valid URL p51
hreflang
a
Language of the linked resource
Valid BCP 47 language code
http-equiv
meta p115
Pragma directive
Text*
icon
command p371
Icon for the command
Valid non-empty URL p51
; area
; link
Attribute
Element(s)
Description
Value
id
HTML elements p84
The element's ID p84
ismap
img p189
Whether the image is a server-side Boolean attribute p34
image map
itemid
HTML elements p405
Global identifier p405 for a microdata Valid URL p51
item
itemprop
HTML elements p405
Property names p406 of a microdata
item
Unordered set of unique spaceseparated tokens p49 consisting of valid
absolute URLs p52 , defined property
names p406 , or text*
itemref
itemref p405
Referenced elements
Unordered set of unique spaceseparated tokens p49 consisting of IDs*
itemscope
HTML elements p405
Introduces a microdata item
Boolean attribute p34
itemtype
HTML elements p405
Item type p405 of a microdata item
Valid absolute URL p52 *
The type of cryptographic key to
generate
Text*
p344
Text*
keytype
keygen
label
command p371 ; menu p373 ; optgroup p339 ;
option p340
User-visible label
Text
lang
HTML elements p85
Language p85 of the element
Valid BCP 47 language code or the
empty string
list
input p324
List of autocomplete options
ID*
loop
audio p229 ; video p229
Whether to loop the media
resource p219
Boolean attribute p34
low
meter p350
High limit of low range
Valid floating point number p36 *
manifest
html p106
Application cache manifest p471
Valid non-empty URL p51
Maximum value
varies*
Upper bound of range
Valid floating point number p36 *
Maximum length of value
Valid non-negative integer p35
Applicable media
Valid media query p51
max
max
maxlength
input
p328
meter
p350
input
p327
p384
; progress
p348
; textarea
p343
p384
p111
p218
media
a
; area
style p120
method
form p355
HTTP method to use for form
submission p360
"GET"; "POST"; "PUT"; "DELETE"
min
input p328
Minimum value
varies*
min
meter p350
Lower bound of range
Valid floating point number p36 *
Whether to allow multiple values
Boolean attribute p34
p327
; link
; source
;
p335
multiple
input
name
button p354 ; fieldset p354 ; input p354 ;
keygen p354 ; output p354 ; select p354 ;
textarea p354
Name of form control to use for
form submission p360 and in the
form.elements p299 API
Text*
name
form p298
Name of form to use in the
document.forms p77 API
Text*
name
iframe p202 ; object p209
Name of nested browsing
context p439
Valid browsing context name or
keyword p442
name
map p265
Name of image map p268 to
reference from the usemap p268
attribute
Text*
name
meta p113
Metadata name
Text*
name
param p213
Name of parameter
Text
novalidate
form p356
Bypass form control validation for
form submission p360
Boolean attribute p34
open
details p367
; select
Whether the details are visible
Boolean attribute p34
meter
p350
Optimum value in gauge
Valid floating point number p36 *
pattern
input
p328
Pattern to be matched by the form
control's value
Regular expression matching the
JavaScript Pattern production
ping
a p384 ; area p384
URLs p51 to ping
Set of space-separated tokens p49
consisting of valid non-empty URLs p51
placeholder
input p329 ; textarea p343
User-visible label to be placed
within the form control
Text*
poster
video p214
Poster frame to show prior to video Valid non-empty URL p51
playback
preload
audio p227 ; video p227
Hints how much buffering the
media resource p219 will likely need
"none p227 "; "metadata p227 "; "auto p227 "
pubdate
time p169
Whether the element's value
represents a publication time for
the nearest article p136 or body p131
Boolean attribute p34
radiogroup
command p372
Name of group of commands to
treat as a radio button group
Text
readonly
input p325 ; textarea p342
Whether to allow the value to be
edited by the user
Boolean attribute p34
optimum
693
Attribute
Description
Value
a p384 ; area p384 ; link p110
Relationship between the
Set of space-separated tokens p49 *
document containing the hyperlink
and the destination resource
required
input p326 ; textarea p343
Whether the control is required for
form submission p360
Boolean attribute p34
reversed
ol p152
Number the list backwards
Boolean attribute p34
Number of lines to show
Valid non-negative integer p35 greater
than zero
p343
rows
textarea
rowspan
td p284 ; th p284
Number of rows that the cell is to
span
Valid non-negative integer p35
sandbox
iframe p202
Security rules for nested content
Unordered set of unique spaceseparated tokens p49 consisting of
"allow-same-origin p203 ", "allowforms p203 ", and "allow-scripts p203 "
spellcheck
HTML elements p521
Whether the element is to have its
spelling and grammar checked
"true"; "false"
scope
th p283
Specifies which cells the header
cell applies to
"row p283 "; "col p283 "; "rowgroup p283 ";
"colgroup p283 "
scoped
style p120
Whether the styles apply to the
entire document or just the parent
subtree
Boolean attribute p34
seamless
iframe p204
Whether to apply the document's
styles to the nested content
Boolean attribute p34
selected
option p340
Whether the option is selected by
default
Boolean attribute p34
shape
area p267
The kind of shape to be created in
an image map p268
"circle p267 "; "default p267 "; "poly p267 ";
"rect p267 "
size
input p326 ; select p335
Size of the control
Valid non-negative integer p35 greater
than zero
sizes
link p389
Sizes of the icons (for
rel p110 ="icon p389 ")
Unordered set of unique spaceseparated tokens p49 consisting of sizes*
span
col p279 ; colgroup p278
Number of columns spanned by
the element
Valid non-negative integer p35 greater
than zero
src
audio p220 ; embed p206 ; iframe p200 ;
img p186 ; input p321 ; script p123 ;
source p217 ; video p220
Address of the resource
Valid non-empty URL p51
srcdoc
iframe p200
A document to render in the
iframe p199
The source of an iframe srcdoc
document p200 *
start
ol p153
Ordinal value of the first item
Valid integer p35
Granularity to be matched by the
form control's value
Valid floating point number p36 greater
than zero, or "any"
p329
step
input
style
HTML elements p86
Presentational and formatting
instructions
CSS declarations*
summary
table p275
Explanatory text for complex
tables for users of screen readers
Text*
tabindex
HTML elements p509
Whether the element is focusable,
and the relative order of the
element for the purposes of
sequential focus navigation
Valid integer p35
target
a p384 ; area p384
Browsing context p439 for
hyperlink p383 navigation p459
Valid browsing context name or
keyword p442
target
base p109
Default browsing context p439 for
hyperlink p383 navigation p459 and
form submission p360
Valid browsing context name or
keyword p442
target
form p356
Browsing context p439 for form
submission p360
Valid browsing context name or
keyword p442
title
HTML elements p84
Advisory information for the
element
Text
title
abbr p167 ; dfn p167
Full term or expansion of
abbreviation
Text
title
command p371
Hint describing the command
Text
title
link p111
Title of the link
Text
title
link p111 ; style p120
Alternative style sheet set name
Text
Hint for the type of the referenced
resource
Valid MIME type p26
Type of button
"submit p333 "; "reset p333 "; "button p333 "
Type of form control
input type keyword p304
Type of command
"command p371 "; "checkbox p371 ";
"radio p371 "
p384
type
a
type
button p333
type
p333
type
694
Element(s)
rel
; area
button
command
p384
; link
; input
p371
p111
p304
Attribute
Element(s)
Description
Value
type
embed p206 ; object p209 ; script p123 ;
source p217 ; style p120
Type of embedded resource
Valid MIME type p26
type
menu p373
Type of menu
"context p373 "; "toolbar p373 "
usemap
img
p268
; object
value
button
value
p334
p268
Name of image map
p340
p268
to use
Valid hash-name reference p50 *
Value to be used for form
submission p360
Text
input p306
Value of the form control
varies*
value
li p154
Ordinal value of the list item
Valid integer p35
value
meter p350 ; progress p348
Current value of the element
Valid floating point number p36
Value of parameter
Text
Horizontal dimension
Valid non-negative integer p35
How the value of the form control
is to be wrapped for form
submission p360
"soft p343 "; "hard p343 "
value
param
; option
p213
p239
p271
p271
width
canvas
; embed
; iframe
img p271 ; input p271 ; object p271 ;
video p271
wrap
textarea p343
;
An asterisk (*) in a cell indicates that the actual rules are more complicated than indicated in the table above.
List of event handler content attributes
Attribute
Element(s)
Description
Value
onabort
HTML
elements p494
abort event handler
Event handler content
attribute p492
onafterprint
body p495
afterprint event handler for Window p443 object
Event handler content
attribute p492
onbeforeprint
body p495
beforeprint event handler for Window p443 object
Event handler content
attribute p492
onbeforeunload
body p495
beforeunload event handler for Window p443 object
Event handler content
attribute p492
onblur
body p495
blur event handler for Window p443 object
Event handler content
attribute p492
onblur
HTML
elements p495
blur event handler
Event handler content
attribute p492
oncanplay
HTML
elements p494
canplay p237 event handler
Event handler content
attribute p492
oncanplaythrough
HTML
elements p494
canplaythrough p237 event handler
Event handler content
attribute p492
onchange
HTML
elements p494
change event handler
Event handler content
attribute p492
onclick
HTML
elements p494
click p31 event handler
Event handler content
attribute p492
oncontextmenu
HTML
elements p494
contextmenu event handler
Event handler content
attribute p492
ondblclick
HTML
elements p494
dblclick event handler
Event handler content
attribute p492
ondrag
HTML
elements p494
drag p526 event handler
Event handler content
attribute p492
ondragend
HTML
elements p494
dragend p526 event handler
Event handler content
attribute p492
ondragenter
HTML
elements p494
dragenter p526 event handler
Event handler content
attribute p492
ondragleave
HTML
elements p494
dragleave p526 event handler
Event handler content
attribute p492
ondragover
HTML
elements p494
dragover p526 event handler
Event handler content
attribute p492
ondragstart
HTML
elements p494
dragstart p526 event handler
Event handler content
attribute p492
ondrop
HTML
elements p494
drop p526 event handler
Event handler content
attribute p492
ondurationchange
HTML
elements p494
durationchange p238 event handler
Event handler content
attribute p492
onemptied
HTML
elements p494
emptied p237 event handler
Event handler content
attribute p492
onended
HTML
elements p494
ended p238 event handler
Event handler content
attribute p492
onerror
body p495
error event handler for Window p443 object, and handler for script
error notifications p496
Event handler content
attribute p492
695
Attribute
Element(s)
Value
HTML
elements p495
error event handler
Event handler content
attribute p492
onfocus
body p495
focus event handler for Window p443 object
Event handler content
attribute p492
onfocus
HTML
elements p495
focus event handler
Event handler content
attribute p492
onformchange
HTML
elements p494
formchange event handler
Event handler content
attribute p492
onforminput
HTML
elements p494
forminput event handler
Event handler content
attribute p492
onhashchange
body p495
hashchange p467 event handler for Window p443 object
Event handler content
attribute p492
oninput
HTML
elements p494
input event handler
Event handler content
attribute p492
oninvalid
HTML
elements p494
invalid event handler
Event handler content
attribute p492
onkeydown
HTML
elements p495
keydown event handler
Event handler content
attribute p492
onkeypress
HTML
elements p495
keypress event handler
Event handler content
attribute p492
onkeyup
HTML
elements p495
keyup event handler
Event handler content
attribute p492
onload
body p495
load event handler for Window p443 object
Event handler content
attribute p492
onload
HTML
elements p495
load event handler
Event handler content
attribute p492
onloadeddata
HTML
elements p495
loadeddata p237 event handler
Event handler content
attribute p492
onloadedmetadata
HTML
elements p495
loadedmetadata p237 event handler
Event handler content
attribute p492
onloadstart
HTML
elements p495
loadstart p237 event handler
Event handler content
attribute p492
onmessage
body p495
message p540 event handler for Window p443 object
Event handler content
attribute p492
onmousedown
HTML
elements p495
mousedown event handler
Event handler content
attribute p492
onmousemove
HTML
elements p495
mousemove event handler
Event handler content
attribute p492
onmouseout
HTML
elements p495
mouseout event handler
Event handler content
attribute p492
onmouseover
HTML
elements p495
mouseover event handler
Event handler content
attribute p492
onmouseup
HTML
elements p495
mouseup event handler
Event handler content
attribute p492
onmousewheel
HTML
elements p495
mousewheel event handler
Event handler content
attribute p492
onoffline
body p495
offline p486 event handler for Window p443 object
Event handler content
attribute p492
ononline
body p495
online p486 event handler for Window p443 object
Event handler content
attribute p492
onpause
HTML
elements p495
pause p237 event handler
Event handler content
attribute p492
onplay
HTML
elements p495
play p237 event handler
Event handler content
attribute p492
onplaying
HTML
elements p495
playing p237 event handler
Event handler content
attribute p492
onpagehide
body p495
pagehide p468 event handler for Window p443 object
Event handler content
attribute p492
onpageshow
body p495
pageshow p468 event handler for Window p443 object
Event handler content
attribute p492
onpopstate
body p495
popstate p467 event handler for Window p443 object
Event handler content
attribute p492
onprogress
HTML
elements p495
progress p237 event handler
Event handler content
attribute p492
onratechange
HTML
elements p495
ratechange p238 event handler
Event handler content
attribute p492
readystatechange event handler
Event handler content
attribute p492
redo p534 event handler for Window p443 object
Event handler content
attribute p492
onreadystatechange HTML
elements p495
onredo
696
Description
onerror
body p495
Attribute
Element(s)
Description
Value
onresize
body p495
resize event handler for Window p443 object
Event handler content
attribute p492
onscroll
HTML
elements p495
scroll event handler
Event handler content
attribute p492
onseeked
HTML
elements p495
seeked p237 event handler
Event handler content
attribute p492
onseeking
HTML
elements p495
seeking p237 event handler
Event handler content
attribute p492
onselect
HTML
elements p495
select event handler
Event handler content
attribute p492
onshow
HTML
elements p495
show event handler
Event handler content
attribute p492
onstalled
HTML
elements p495
stalled p237 event handler
Event handler content
attribute p492
onstorage
body p496
storage event handler for Window p443 object
Event handler content
attribute p492
onsubmit
HTML
elements p495
submit event handler
Event handler content
attribute p492
onsuspend
HTML
elements p495
suspend p237 event handler
Event handler content
attribute p492
ontimeupdate
HTML
elements p495
timeupdate p237 event handler
Event handler content
attribute p492
onundo
body p496
undo p534 event handler for Window p443 object
Event handler content
attribute p492
onunload
body p496
unload event handler for Window p443 object
Event handler content
attribute p492
onvolumechange
HTML
elements p495
volumechange p238 event handler
Event handler content
attribute p492
onwaiting
HTML
elements p495
waiting p237 event handler
Event handler content
attribute p492
Interfaces
This section is non-normative.
List of interfaces for elements
Element(s)
Interface(s)
a p160
HTMLAnchorElement p161 : HTMLElement p81
abbr p167
HTMLElement p81
address p143
HTMLElement p81
area p266
HTMLAreaElement p266 : HTMLElement p81
article
p136
HTMLElement p81
aside
p137
HTMLElement p81
audio
p216
HTMLAudioElement p216 : HTMLMediaElement p219 : HTMLElement p81
b
p175
base
HTMLElement p81
p108
HTMLBaseElement p108 : HTMLElement p81
bdo p180
HTMLElement p81
blockquote p151 HTMLQuoteElement p151 : HTMLElement p81
body p131
br
HTMLBodyElement p132 : HTMLElement p81
p181
HTMLBRElement p181 : HTMLElement p81
button
p332
HTMLButtonElement p333 : HTMLElement p81
canvas
p238
HTMLCanvasElement p238 : HTMLElement p81
caption
p277
HTMLTableCaptionElement p277 : HTMLElement p81
cite p165
HTMLElement p81
p171
HTMLElement p81
code
col
p279
HTMLTableSectionElement p279 : HTMLElement p81
colgroup
command
p278
p371
datalist
p338
dd p157
div
dl
p159
p155
HTMLCommandElement p371 : HTMLElement p81
HTMLDataListElement p338 : HTMLElement p81
HTMLElement p81
del p183
details
HTMLTableColElement p278 : HTMLElement p81
HTMLModElement p184 : HTMLElement p81
p367
HTMLDetailsElement p367 : HTMLElement p81
HTMLDivElement p160 : HTMLElement p81
HTMLDListElement p155 : HTMLElement p81
697
Element(s)
dt p157
em p162
embed
HTMLElement p81
p205
HTMLEmbedElement p206 : HTMLElement p81
fieldset p300
figcaption
p159
HTMLFieldSetElement p300 : HTMLElement p81
HTMLElement p81
figure
p158
HTMLElement p81
footer
p142
HTMLElement p81
form
p297
HTMLFormElement p297 : HTMLElement p81
head
p106
HTMLHeadElement p107 : HTMLElement p81
h1 p139
HTMLHeadingElement p139 : HTMLElement p81
h2 p139
HTMLHeadingElement p139 : HTMLElement p81
h3
p139
HTMLHeadingElement p139 : HTMLElement p81
h4
p139
HTMLHeadingElement p139 : HTMLElement p81
h5
p139
HTMLHeadingElement p139 : HTMLElement p81
h6
p139
HTMLHeadingElement p139 : HTMLElement p81
p140
HTMLElement p81
hgroup p140
HTMLElement p81
hr p149
HTMLHRElement p149 : HTMLElement p81
header
html
i
p106
HTMLHtmlElement p106 : HTMLElement p81
p174
HTMLElement p81
iframe
img
p199
p186
input
kbd
HTMLInputElement p303 : HTMLElement p81
label
HTMLElement p81
p344
p301
legend
li
HTMLModElement p184 : HTMLElement p81
p173
keygen
HTMLIFrameElement p200 : HTMLElement p81
HTMLImageElement p186 : HTMLElement p81
p303
ins p182
HTMLKeygenElement p344 : HTMLElement p81
HTMLLabelElement p302 : HTMLElement p81
p301
p154
HTMLLegendElement p301 : HTMLElement p81
HTMLLIElement p154 : HTMLElement p81
link p109
HTMLLinkElement p109 : HTMLElement p81
map p265
HTMLMapElement p265 : HTMLElement p81
mark
p176
meter
nav
HTMLElement p81
p349
HTMLMeterElement p350 : HTMLElement p81
p134
HTMLElement p81
noscript
object
p129
p208
ol p152
HTMLElement p81
HTMLObjectElement p208 : HTMLElement p81
HTMLOListElement p152 : HTMLElement p81
optgroup p338
HTMLOptGroupElement p338 : HTMLElement p81
option
p339
HTMLOptionElement p340 : HTMLElement p81
output
p346
HTMLOutputElement p346 : HTMLElement p81
p
p148
HTMLParagraphElement p148 : HTMLElement p81
param
pre
p213
p150
q
HTMLParamElement p213 : HTMLElement p81
HTMLPreElement p150 : HTMLElement p81
progress p348
p166
HTMLProgressElement p348 : HTMLElement p81
HTMLElement p81
rp
p179
HTMLElement p81
rt
p179
HTMLElement p81
ruby
p177
HTMLElement p81
samp
p172
HTMLElement p81
section p133
HTMLElement p81
select p334
HTMLSelectElement p335 : HTMLElement p81
small
p164
source
span
p217
p180
strong
style
p163
p119
HTMLElement p81
HTMLSourceElement p217 : HTMLElement p81
HTMLSpanElement p180 : HTMLElement p81
HTMLElement p81
HTMLStyleElement p119 : HTMLElement p81
sub p174
HTMLElement p81
summary p370
HTMLElement p81
sup
p174
table
698
Interface(s)
HTMLElement p81
p271
HTMLElement p81
HTMLTableElement p272 : HTMLElement p81
Element(s)
Interface(s)
td p282
HTMLTableDataCellElement p282 : HTMLTableCellElement p285 : HTMLElement p81
textarea p341
HTMLTextAreaElement p342 : HTMLElement p81
th
p283
HTMLTableHeaderCellElement p283 : HTMLTableCellElement p285 : HTMLElement p81
thead p280
time
title
ul
HTMLTableRowElement p281 : HTMLElement p81
p168
HTMLTimeElement p169 : HTMLElement p81
p107
HTMLTitleElement p107 : HTMLElement p81
p153
var
HTMLUListElement p153 : HTMLElement p81
p172
video
HTMLElement p81
p213
HTMLVideoElement p214 : HTMLMediaElement p219 : HTMLElement p81
wbr p181
HTMLElement p81
Events
This section is non-normative.
List of events
Event
DOMActivate p31
Interface
Description
Event p31
Fired at an element before its activation behavior p93 is run
DOMContentLoaded Event p31
Fired at the Document p31 once it and its scripts have loaded, without waiting for other
subresources
Event p31
abort
Fired at the Window p443 when the download was aborted by the user
p31
Fired at the Window p443 after printing
afterprint
Event
beforeprint
Event p31
Fired at the Window p443 before printing
beforeunload
BeforeUnloadEvent p469
Fired at the Window p443 when the page is about to be unloaded, in case the page would
like to show a warning prompt
blur
Event p31
Fired at nodes losing focus
change
Event p31
Fired at controls when the user commits a value change
contextmenu
Event p31
Fired at elements when the user requests their context menu
error
Event p31
Fired at elements when network and script errors occur
focus
Event p31
Fired at nodes gaining focus
p31
formchange
Event
forminput
Event p31
Fired at form controls when the user commits a value change to a control on the form
Fired at form controls when the user changes the value of a control on the form
hashchange p467
HashChangeEvent p467
Fired at the Window p443 when the fragment identifier part of the document's current
address p71 changes
input
Event p31
Fired at controls when the user changes the value
Event
p31
Fired at controls during form validation if they do not satisfy their constraints
load
Event
p31
Fired at the Window p443 when the document has finished loading; fired at an element
containing a resource (e.g. img p186 , embed p205 ) when its resource has finished loading
message p540
MessageEvent p540
Fired at an object when the object receives a message
offline p486
Event p31
Fired at the Window p443 when the network connections fails
invalid
online
p486
pagehide
p468
Event
p31
Fired at the Window p443 when the network connections returns
PageTransitionEvent
p468
Fired at the Window p443 when the page's entry in the session history p453 stops being the
current entry p453
pageshow p468
PageTransitionEvent p468 Fired at the Window p443 when the page's entry in the session history p453 becomes the
current entry p453
popstate p467
PopStateEvent p467
readystatechange Event
Fired at the Window p443 when the user navigates the session history p453
p31
Fired at the Document p31 when it finishes parsing and again when all its subresources
have finished loading
redo p534
UndoManagerEvent p534
Fired at the Window p443 object when the user goes forward in the undo transaction
history p534
reset
Event p31
Fired at a form p297 element when it is reset p366
show
submit
undo
p534
unload
Event
p31
Event
p31
UndoManagerEvent
Event p31
Fired at a menu p372 element when it is shown as a context menu
Fired at a form p297 element when it is submitted p361
p534
Fired at the Window p443 object when the user goes backward in the undo transaction
history p534
Fired at the Window p443 object when the page is going away
Note: See also media element events p237 , application cache events p471 , and drag-and-drop
events p526 .
699
References
All references are normative unless marked "Non-normative".
[ABNF]
Augmented BNF for Syntax Specifications: ABNF, D. Crocker, P. Overell. IETF.
[ABOUT]
The 'about' URI scheme, J. Holsten, L. Hunt. IETF.
[ARIA]
Accessible Rich Internet Applications (WAI-ARIA), J. Craig, M. Cooper, L. Pappas, R. Schwerdtfeger, L. Seeman.
W3C.
[ARIAIMPL]
WAI-ARIA 1.0 User Agent Implementation Guide, A. Snow-Weaver, M. Cooper. W3C.
[ATAG]
(Non-normative) Authoring Tool Accessibility Guidelines (ATAG) 2.0, J. Richards, J. Spellman, J. Treviranus.
W3C.
[ATOM]
(Non-normative) The Atom Syndication Format, M. Nottingham, R. Sayre. IETF.
[BCP47]
Tags for Identifying Languages; Matching of Language Tags, A. Phillips, M. Davis. IETF.
[BECSS]
Behavioral Extensions to CSS, I. Hickson. W3C.
[BEZIER]
Courbes à poles, P. de Casteljau. INPI, 1959.
[BIDI]
UAX #9: Unicode Bidirectional Algorithm, M. Davis. Unicode Consortium.
[BOCU1]
(Non-normative) UTN #6: BOCU-1: MIME-Compatible Unicode Compression, M. Scherer, M. Davis. Unicode
Consortium.
[CESU8]
(Non-normative) UTR #26: Compatibility Encoding Scheme For UTF-16: 8-BIT (CESU-8), T. Phipps. Unicode
Consortium.
[CHARMOD]
(Non-normative) Character Model for the World Wide Web 1.0: Fundamentals, M. Dürst, F. Yergeau, R. Ishida,
M. Wolf, T. Texin. W3C.
[COMPUTABLE]
(Non-normative) On computable numbers, with an application to the Entscheidungsproblem, A. Turing. In
Proceedings of the London Mathematical Society, series 2, volume 42, pages 230-265. London Mathematical
Society, 1937.
[COOKIES]
HTTP State Management Mechanism, A. Barth. IETF.
[CORS]
Cross-Origin Resource Sharing, A. van Kesteren. W3C.
[CSS]
Cascading Style Sheets Level 2 Revision 1, B. Bos, T. Çelik, I. Hickson, H. Lie. W3C.
[CSSATTR]
CSS Styling Attribute Syntax, E. Etemad. W3C.
[CSSCOLOR]
CSS Color Module Level 3, T. Çelik, C. Lilley, L. Baron. W3C.
[CSSFONTS]
CSS Fonts Module Level 3, J. Daggett. W3C.
[CSSOM]
Cascading Style Sheets Object Model (CSSOM), A. van Kesteren. W3C.
700
[CSSUI]
CSS3 Basic User Interface Module, T. Çelik. W3C.
[DOMCORE]
Document Object Model (DOM) Level 3 Core Specification, A. Le Hors, P. Le Hegaret, L. Wood, G. Nicol, J.
Robie, M. Champion, S. Byrnes. W3C.
[DOMEVENTS]
Document Object Model (DOM) Level 3 Events Specification, D. Schepers. W3C.
[DOMRANGE]
Document Object Model (DOM) Level 2 Traversal and Range Specification, J. Kesselman, J. Robie, M.
Champion, P. Sharpe, V. Apparao, L. Wood. W3C.
[E163]
Recommendation E.163 — Numbering Plan for The International Telephone Service, CCITT Blue Book,
Fascicle II.2, pp. 128-134, November 1988.
[ECMA262]
ECMAScript Language Specification. ECMA.
[ECMA357]
(Non-normative) ECMAScript for XML (E4X) Specification. ECMA.
[EUCKR]
Hangul Unix Environment. Korea Industrial Standards Association. Ref. No. KS C 5861-1992.
[EVENTSOURCE]
Server-Sent Events, I. Hickson. W3C.
[FILEAPI]
File API, A. Ranganathan. W3C.
[GBK]
Chinese Internal Code Specification. Chinese IT Standardization Technical Committee.
[GRAPHICS]
(Non-normative) Computer Graphics: Principles and Practice in C, Second Edition, J. Foley, A. van Dam, S.
Feiner, J. Hughes. Addison-Wesley. ISBN 0-201-84840-6.
[GREGORIAN]
(Non-normative) Inter Gravissimas, A. Lilius, C. Clavius. Gregory XIII Papal Bulls, February 1582.
[HATOM]
(Non-normative) hAtom, D Janes. Microformats.
[HTMLDIFF]
(Non-normative) HTML5 differences from HTML4, A. van Kesteren. W3C.
[HTTP]
Hypertext Transfer Protocol — HTTP/1.1, R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P. Leach, T.
Berners-Lee. IETF.
[IANACHARSET]
Character Sets. IANA.
[IANAPERMHEADERS]
Permanent Message Header Field Names. IANA.
[ISO8601]
ISO8601: Data elements and interchange formats — Information interchange — Representation of dates and
times. ISO.
[ISO885911]
ISO-8859-11: Information technology — 8-bit single-byte coded graphic character sets — Part 11: Latin/Thai
alphabet. ISO.
[JSON]
The application/json Media Type for JavaScript Object Notation (JSON), D. Crockford. IETF.
[JSURL]
The 'javascript' resource identifier scheme, B. Höhrmann. IETF.
[MAILTO]
The mailto URL scheme, P. Hoffman, L. Masinter, J. Zawinski. IETF.
701
[MATHML]
Mathematical Markup Language (MathML), D. Carlisle, P. Ion, R. Miner, N. Poppelier. W3C.
[MIMESNIFF]
Content-Type Processing Model, A. Barth, I. Hickson. IETF.
[MQ]
Media Queries, H. Lie, T. Çelik, D. Glazman, A. van Kesteren. W3C.
[NPAPI]
(Non-normative) Gecko Plugin API Reference. Mozilla.
[OPENSEARCH]
Autodiscovery in HTML/XHTML. In OpenSearch 1.1 Draft 4, Section 4.6.2. OpenSearch.org.
[ORIGIN]
The HTTP Origin Header, A. Barth, C. Jackson, I. Hickson. IETF.
[PINGBACK]
Pingback 1.0, S. Langridge, I. Hickson.
[PNG]
Portable Network Graphics (PNG) Specification, D. Duce. W3C.
[PORTERDUFF]
Compositing Digital Images, T. Porter, T. Duff. In Computer graphics, volume 18, number 3, pp. 253-259.
ACM Press, July 1984.
[PPUTF8]
(Non-normative) The Properties and Promises of UTF-8, M. Dürst. University of Zürich. In Proceedings of the
11th International Unicode Conference.
[PROGRESS]
Progress Events, C. McCathieNevile. W3C.
[PSL]
Public Suffix List. Mozilla Foundation.
[RFC1034]
Domain Names - Concepts and Facilities, P. Mockapetris. IETF, November 1987.
[RFC1345]
Character Mnemonics and Character Sets, K. Simonsen. IETF.
[RFC1468]
Japanese Character Encoding for Internet Messages, J. Murai, M. Crispin, E. van der Poel. IETF.
[RFC1554]
ISO-2022-JP-2: Multilingual Extension of ISO-2022-JP, M. Ohta, K. Handa. IETF.
[RFC1557]
Korean Character Encoding for Internet Messages, U. Choi, K. Chon, H. Park. IETF.
[RFC1842]
ASCII Printable Characters-Based Chinese Character Encoding for Internet Messages, Y. Wei, Y. Zhang, J. Li, J.
Ding, Y. Jiang. IETF.
[RFC1922]
Chinese Character Encoding for Internet Messages, HF. Zhu, DY. Hu, ZG. Wang, TC. Kao, WCH. Chang, M.
Crispin. IETF.
[RFC2045]
Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies, N. Freed, N.
Borenstein. IETF.
[RFC2046]
Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types, N. Freed, N. Borenstein. IETF.
[RFC2119]
Key words for use in RFCs to Indicate Requirement Levels, S. Bradner. IETF.
[RFC2237]
Japanese Character Encoding for Internet Messages, K. Tamaru. IETF.
[RFC2313]
PKCS #1: RSA Encryption, B. Kaliski. IETF.
702
[RFC2318]
The text/css Media Type, H. Lie, B. Bos, C. Lilley. IETF.
[RFC2388]
Returning Values from Forms: multipart/form-data, L. Masinter. IETF.
[RFC2425]
A MIME Content-Type for Directory Information, T. Howes, M. Smith, F. Dawson. IETF.
[RFC2426]
vCard MIME Directory Profile, F. Dawson, T. Howes. IETF.
[RFC2445]
Internet Calendaring and Scheduling Core Object Specification (iCalendar), F. Dawson, D. Stenerson. IETF.
[RFC2483]
URI Resolution Services Necessary for URN Resolution, M. Mealling, R. Daniel. IETF.
[RFC2781]
UTF-16, an encoding of ISO 10646, P. Hoffman, F. Yergeau. IETF.
[RFC2646]
The Text/Plain Format Parameter, R. Gellens. IETF.
[RFC3023]
XML Media Types, M. Murata, S. St. Laurent, D. Kohn. IETF.
[RFC3279]
Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile, W. Polk, R. Housley, L. Bassham. IETF.
[RFC3490]
Internationalizing Domain Names in Applications (IDNA), P. Faltstrom, P. Hoffman, A. Costello. IETF.
[RFC3548]
The Base16, Base32, and Base64 Data Encodings, S. Josefsson. IETF.
[RFC3864]
Registration Procedures for Message Header Fields, G. Klyne, M. Nottingham, J. Mogul. IETF.
[RFC3986]
Uniform Resource Identifier (URI): Generic Syntax, T. Berners-Lee, R. Fielding, L. Masinter. IETF.
[RFC3987]
Internationalized Resource Identifiers (IRIs), M. Dürst, M. Suignard. IETF.
[RFC4281]
The Codecs Parameter for "Bucket" Media Types, R. Gellens, D. Singer, P. Frojdh. IETF.
[RFC4329]
(Non-normative) Scripting Media Types, B. Höhrmann. IETF.
[RFC4770]
vCard Extensions for Instant Messaging (IM), C. Jennings, J. Reschke. IETF.
[RFC5280]
Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile, D. Cooper, S.
Santesson, S. Farrell, S. Boeyen, R. Housley, W. Polk. IETF.
[RFC5322]
Internet Message Format, P. Resnick. IETF.
[RFC5724]
URI Scheme for Global System for Mobile Communications (GSM) Short Message Service (SMS), E. Wilde, A.
Vaha-Sipila. IETF.
[SCSU]
(Non-normative) UTR #6: A Standard Compression Scheme For Unicode, M. Wolf, K. Whistler, C. Wicksteed,
M. Davis, A. Freytag, M. Scherer. Unicode Consortium.
[SELECTORS]
Selectors, T. Çelik, E. Etemad, D. Glazman, I. Hickson, P. Linss, J. Williams. W3C.
[SHIFTJIS]
JIS X0208: 7-bit and 8-bit double byte coded KANJI sets for information interchange. Japanese Standards
Association.
703
[SRGB]
IEC 61966-2-1: Multimedia systems and equipment — Colour measurement and management — Part 2-1:
Colour management — Default RGB colour space — sRGB. IEC.
[SVG]
Scalable Vector Graphics (SVG) Tiny 1.2 Specification, O. Andersson, R. Berjon, E. Dahlström, A. Emmons, J.
Ferraiolo, A. Grasso, V. Hardy, S. Hayman, D. Jackson, C. Lilley, C. McCormack, A. Neumann, C. Northway, A.
Quint, N. Ramani, D. Schepers, A. Shellshear. W3C.
[TIS620]
UDC 681.3.04:003.62. Thai Industrial Standards Institute, Ministry of Industry, Royal Thai Government. ISBN
974-606-153-4.
[UAAG]
(Non-normative) Web Content Accessibility Guidelines (UAAG) 2.0, J. Allan, K. Ford, J. Richards, J. Spellman.
W3C.
[UNICODE]
The Unicode Standard. Unicode Consortium.
[UNIVCHARDET]
(Non-normative) A composite approach to language/encoding detection, S. Li, K. Momoi. Netscape. In
Proceedings of the 19th International Unicode Conference.
[UTF7]
UTF-7: A Mail-Safe Transformation Format of Unicode, D. Goldsmith, M. Davis. IETF.
[UTF8DET]
(Non-normative) Multilingual form encoding, M. Dürst. W3C.
[UTR36]
(Non-normative) UTR #36: Unicode Security Considerations, M. Davis, M. Suignard. Unicode Consortium.
[WCAG]
(Non-normative) Web Content Accessibility Guidelines (WCAG) 2.0, B. Caldwell, M. Cooper, L. Reid, G.
Vanderheiden. W3C.
[WEBIDL]
Web IDL, C. McCormack. W3C.
[WEBLINK]
Web Linking, M. Nottingham. IETF.
[WEBSOCKET]
The WebSocket API, I. Hickson. W3C.
[WEBSQL]
Web SQL Database, I. Hickson. W3C.
[WEBSTORAGE]
Web Storage, I. Hickson. W3C.
[WEBWORKERS]
Web Workers, I. Hickson. W3C.
[WHATWGWIKI]
The WHATWG Wiki. WHATWG.
[WIN1252]
Windows 1252. Microsoft.
[WIN1254]
Windows 1254. Microsoft.
[WIN31J]
Windows Codepage 932. Microsoft.
[WIN874]
Windows 874. Microsoft.
[WIN949]
Windows Codepage 949. Microsoft.
[X121]
Recommendation X.121 — International Numbering Plan for Public Data Networks, CCITT Blue Book, Fascicle
VIII.3, pp. 317-332.
704
[X690]
Recommendation X.690 — Information Technology — ASN.1 Encoding Rules — Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER).
International Telecommunication Union.
[XHR]
XMLHttpRequest, A. van Kesteren. W3C.
[XML]
Extensible Markup Language, T. Bray, J. Paoli, C. Sperberg-McQueen, E. Maler, F. Yergeau. W3C.
[XMLBASE]
XML Base, J. Marsh, R. Tobin. W3C.
[XMLNS]
Namespaces in XML, T. Bray, D. Hollander, A. Layman, R. Tobin. W3C.
[XPATH10]
XML Path Language (XPath) Version 1.0, J. Clark, S. DeRose. W3C.
[XSLT10]
XSL Transformations (XSLT) Version 1.0, J. Clark. W3C.
705
Acknowledgements
Thanks to Aankhen, Aaron Boodman, Aaron Leventhal, Adam Barth, Adam de Boor, Adam Hepton, Adam Roben,
Addison Phillips, Adele Peterson, Adrian Bateman, Adrian Sutton, Agustín Fernández, Ajai Tirumali, Akatsuki
Kitamura, Alan Plum, Alastair Campbell, Alex Bishop, Alex Nicolaou, Alex Rousskov, Alexander J. Vincent, Alexey
Feldgendler, Алексей Проскуряков (Alexey Proskuryakov), Alexis Deveria, Allan Clements, Amos Jeffries, Anders
Carlsson, Andreas, Andrei Popescu, André E. Veltstra, Andrew Clover, Andrew Gove, Andrew Grieve, Andrew
Oakley, Andrew Sidwell, Andrew Smith, Andrew W. Hagen, Andrey V. Lukyanov, Andy Heydon, Andy Palay, Anne
van Kesteren, Anthony Boyd, Anthony Bryan, Anthony Hickson, Anthony Ricaud, Antti Koivisto, Aron Spohr, Arphen
Lin, Aryeh Gregor, Asbjørn Ulsberg, Ashley Sheridan, Atsushi Takayama, Aurelien Levy, Ave Wrigley, Ben Boyle,
Ben Godfrey, Ben Lerner, Ben Leslie, Ben Meadowcroft, Ben Millard, Benjamin Carl Wiley Sittler, Benjamin HawkesLewis, Bert Bos, Bijan Parsia, Bil Corry, Bill Mason, Bill McCoy, Billy Wong, Bjartur Thorlacius, Björn Höhrmann,
Blake Frantz, Boris Zbarsky, Brad Fults, Brad Neuberg, Brady Eidson, Brendan Eich, Brenton Simpson, Brett Wilson,
Brett Zamir, Brian Campbell, Brian Korver, Brian Kuhn, Brian Ryner, Brian Smith, Brian Wilson, Bryan Sullivan,
Bruce D'Arcus, Bruce Lawson, Bruce Miller, C. Williams, Cameron McCormack, Cao Yipeng, Carlos Gabriel Cardona,
Carlos Perelló Marín, Chao Cai, 윤석찬 (Channy Yun), Charl van Niekerk, Charles Iliya Krempeaux, Charles
McCathieNevile, Chris Cressman, Chris Evans, Chris Morris, Chris Pearce, Christian Biesinger, Christian Johansen,
Christian Schmidt, Christopher Aillon, Chriswa, Cole Robison, Colin Fine, Collin Jackson, Corprew Reed, Craig
Cockburn, Csaba Gabor, Csaba Marton, Daniel Barclay, Daniel Bratell, Daniel Brooks, Daniel Brumbaugh Keeney,
Daniel Cheng, Daniel Davis, Daniel Glazman, Daniel Peng, Daniel Schattenkirchner, Daniel Spång, Daniel
Steinberg, Danny Sullivan, Darin Adler, Darin Fisher, Darxus, Dave Camp, Dave Hodder, Dave Lampton, Dave
Singer, Dave Townsend, David Baron, David Bloom, David Bruant, David Carlisle, David E. Cleary, David Egan
Evans, David Flanagan, David Gerard, David Håsäther, David Hyatt, David I. Lehn, David Matja, David Remahl,
David Smith, David Woolley, DeWitt Clinton, Dean Edridge, Dean Edwards, Debi Orton, Derek Featherstone,
Devdatta, Dimitri Glazkov, Dimitry Golubovsky, Divya Manian, dolphinling, Dominique Hazaël-Massieux, Don
Brutzman, Doron Rosenberg, Doug Kramer, Drew Wilson, Edmund Lai, Eduard Pascual, Eduardo Vela, Edward
O'Connor, Edward Welbourne, Edward Z. Yang, Eira Monstad, Eitan Adler, Eliot Graff, Elizabeth Castro, Elliott
Sprehn, Elliotte Harold, Eric Carlson, Eric Law, Eric Rescorla, Erik Arvidsson, Evan Martin, Evan Prodromou, Evert,
fantasai, Felix Sasaki, Francesco Schwarz, Francis Brosnan Blazquez, Franck 'Shift' Quélain, Frank Barchard, 鵜飼文
敏 (Fumitoshi Ukai), Futomi Hatano, Gavin Carothers, Gareth Rees, Garrett Smith, Geoffrey Garen, Geoffrey
Sneddon, George Lund, Gianmarco Armellin, Giovanni Campagna, Graham Klyne, Greg Botten, Greg Houston, Greg
Wilkins, Gregg Tavares, Grey, Gytis Jakutonis, Håkon Wium Lie, Hallvord Reiar Michaelsen Steen, Hans S.
Tømmerhalt, Henri Sivonen, Henrik Lied, Henry Mason, Hugh Winkler, Ian Bicking, Ian Davis, Ignacio Javier, Ivan
Enderlin, Ivo Emanuel Gonçalves, J. King, Jacques Distler, James Craig, James Graham, James Justin Harrell, James
M Snell, James Perrett, James Robinson, Jan-Klaas Kollhof, Jason Kersey, Jason Lustig, Jason White, Jasper BryantGreene, Jatinder Mann, Jed Hartman, Jeff Balogh, Jeff Cutsinger, Jeff Schiller, Jeff Walden, Jeffrey Zeldman, 胡慧鋒
(Jennifer Braithwaite), Jens Bannmann, Jens Fendler, Jens Lindström, Jens Meiert, Jeremy Keith, Jeremy Orlow,
Jeroen van der Meer, Jian Li, Jim Jewett, Jim Ley, Jim Meehan, Jjgod Jiang, João Eiras, Joe Clark, Joe Gregorio, Joel
Spolsky, Johan Herland, John Boyer, John Bussjaeger, John Carpenter, John Fallows, John Foliot, John Harding, John
Keiser, John Snyders, John-Mark Bell, Johnny Stenback, Jon Ferraiolo, Jon Gibbins, Jon Perlow, Jonas Sicking,
Jonathan Cook, Jonathan Rees, Jonathan Worent, Jonny Axelsson, Jorgen Horstink, Jorunn Danielsen Newth, Joseph
Kesselman, Joseph Pecoraro, Josh Aas, Josh Levenberg, Joshua Randall, Jukka K. Korpela, Jules Clément-Ripoche,
Julian Reschke, Justin Lebar, Justin Sinclair, Kai Hendry, Kartikaya Gupta, Kathy Walton, Kelly Norton, Kevin Benson,
Kornél Pál, Kornel Lesinski, Kristof Zelechovski, 黒澤剛志 (Kurosawa Takeshi), Kyle Hofmann, Léonard Bouchet,
Lachlan Hunt, Larry Masinter, Larry Page, Lars Gunther, Lars Solberg, Laura Granka, Laura L. Carlson, Laura
Wisewell, Laurens Holst, Lee Kowalkowski, Leif Halvard Silli, Lenny Domnitser, Leons Petrazickis, Lobotom Dysmon,
Logan, Loune, Luke Kenneth Casson Leighton, Maciej Stachowiak, Magnus Kristiansen, Maik Merten, Malcolm
Rowe, Mark Birbeck, Mark Miller, Mark Nottingham, Mark Pilgrim, Mark Rowe, Mark Schenk, Mark Wilton-Jones,
Martijn Wargers, Martin Atkins, Martin Dürst, Martin Honnen, Martin Kutschker, Martin Thomson, Masataka Yakura,
Mathieu Henri, Matt Schmidt, Matt Wright, Matthew Gregan, Matthew Mastracci, Matthew Raymond, Matthew
Thomas, Mattias Waldau, Max Romantschuk, Menno van Slooten, Micah Dubinko, Michael 'Ratt' Iannarelli, Michael
A. Nachbaur, Michael A. Puls II, Michael Carter, Michael Daskalov, Michael Enright, Michael Gratton, Michael
Nordman, Michael Powers, Michael(tm) Smith, Michal Zalewski, Michel Fortin, Michelangelo De Simone, Michiel van
der Blonk, Mihai Şucan, Mike Brown, Mike Dierken, Mike Dixon, Mike Schinkel, Mike Shaver, Mikko Rantalainen,
Mohamed Zergaoui, Ms2ger, NARUSE Yui, Neil Deakin, Neil Rashbrook, Neil Soiffer, Nicholas Shanks, Nicholas
Stimpson, Nicholas Zakas, Nicolas Gallagher, Noah Mendelsohn, Noah Slater, Ojan Vafai, Olaf Hoffmann, Olav
Junker Kjær, Oldřich Vetešník, Oliver Hunt, Oliver Rigby, Olivier Gendrin, Olli Pettay, Patrick H. Lauke, Paul Norman,
Per-Erik Brodin, Perry Smith, Peter Karlsson, Peter Kasting, Peter Stark, Peter-Paul Koch, Phil Pickering, Philip
Jägenstedt, Philip Taylor, Philip TAYLOR, Prateek Rungta, Rachid Finge, Rajas Moonka, Ralf Stoltze, Ralph Giles,
Raphael Champeimont, Remco, Remy Sharp, Rene Saarsoo, Rene Stach, Ric Hardacre, Rich Doughty, Richard
Ishida, Rigo Wenning, Rikkert Koppes, Rimantas Liubertas, Rob Ennals, Rob Jellinghaus, Robert Blaut, Robert
Collins, Robert O'Callahan, Robert Sayre, Robin Berjon, Roland Steiner, Roman Ivanov, Roy Fielding, Ryan King, S.
Mike Dierken, Sam Dutton, Sam Kuper, Sam Ruby, Sam Weinig, Sander van Lambalgen, Sarven Capadisli, Scott
González, Scott Hess, Sean Fraser, Sean Hogan, Sean Knapp, Sebastian Markbåge, Sebastian Schnitzenbaumer,
Seth Call, Shanti Rao, Shaun Inman, Shiki Okasaka, Sierk Bornemann, Sigbjørn Vik, Silvia Pfeiffer, Simon Montagu,
Simon Pieters, Simon Spiegel, skeww, Stefan Haustein, Stefan Santesson, Steffen Meschkat, Stephen Ma, Steve
Faulkner, Steve Runyon, Steven Bennett, Steven Garrity, Steven Tate, Stewart Brodie, Stuart Ballard, Stuart
Parmenter, Subramanian Peruvemba, Sunava Dutta, Susan Borgrink, Susan Lesch, Sylvain Pasche, T. J. Crowder,
Tantek Çelik, 田村健人 (TAMURA Kent), Ted Mielczarek, Terrence Wood, Thomas Broyer, Thomas O'Connor, Tim
706
Altman, Tim Johansson, Toby Inkster, Todd Moody, Tom Pike, Tommy Thorsen, Travis Leithead, Tyler Close, Vladimir
Katardjiev, Vladimir Vukićević, voracity, Wakaba, Wayne Pollock, Wellington Fernando de Macedo, Will Levine,
William Swanson, Wladimir Palant, Wojciech Mach, Wolfram Kriesing, Yang Chen, Yehuda Katz, Yi-An Huang, Yngve
Nysaeter Pettersen, Yuzo Fujishima, Zhenbin Xu, Zoltan Herczeg, and Øistein E. Andersen, for their useful
comments, both large and small, that have led to changes to this specification over the years.
Thanks also to everyone who has ever posted about HTML to their blogs, public mailing lists, or forums, including
all the contributors to the various W3C HTML WG lists and the various WHATWG lists.
Special thanks to Richard Williamson for creating the first implementation of canvas p238 in Safari, from which the
canvas feature was designed.
Special thanks also to the Microsoft employees who first implemented the event-based drag-and-drop mechanism,
contenteditable p518 , and other features first widely deployed by the Windows Internet Explorer browser.
Thanks to the participants of the microdata usability study for allowing us to use their mistakes as a guide for
designing the microdata feature.
Special thanks and $10,000 to David Hyatt who came up with a broken implementation of the adoption agency
algorithm p602 that the editor had to reverse engineer and fix before using it in the parsing section.
Thanks to the many sources that provided inspiration for the examples used in the specification.
Thanks also to the Microsoft blogging community for some ideas, to the attendees of the W3C Workshop on Web
Applications and Compound Documents for inspiration, to the #mrt crew, the #mrt.no crew, and the #whatwg
crew, and to Pillar and Hedral for their ideas and support.
707
Carouge.
There is a small mailbox here.
ΑΒΓ company, a small Greek company
specializing in our type of product.
Note that "sales graph" would be inadequate alternative text for a sales graph. Text that would be a
good caption is not generally suitable as replacement text.
Images that defy a complete description
In certain cases, the nature of the image might be such that providing thorough alternative text is
impractical. For example, the image could be indistinct, or could be a complex fractal, or could be a detailed
topographical map.
In these cases, the alt p186 attribute must contain some suitable alternative text, but it may be somewhat
brief.
Sometimes there simply is no text that can do justice to an image. For example, there is little that can
be said to usefully describe a Rorschach inkblot test. However, a description, even if brief, is still
better than nothing:
Images whose contents are not known
In some unfortunate cases, there might be no alternative text available at all, either because the image is
obtained in some automated fashion without any associated alternative text (e.g. a Webcam), or because
196
the page is being generated by a script using user-provided images where the user did not provide suitable
or usable alternative text (e.g. photograph sharing sites), or because the author does not himself know what
the images represent (e.g. a blind photographer sharing an image on his blog).
In such cases, the alt p186 attribute's value may be omitted, but one of the following conditions must be met
as well:
•
The title p84 attribute is present and has a non-empty value.
•
The img p186 element is in a figure p158 element that contains a figcaption p159 element that
contains content other than inter-element whitespace p89 .
•
The img p186 element is part of the only paragraph p93 directly in its section p145 , and is the only
img p186 element without an alt p186 attribute in its section, and its section p145 has an associated
heading.
Note: Such cases are to be kept to an absolute minimum. If there is even the slightest
possibility of the author having the ability to provide real alternative text, then it would
not be acceptable to omit the alt p186 attribute.
A photo on a photo-sharing site, if the site received the image with no metadata other than the
caption:
