HTML is the core language of the World Wide Web. The W3C publishes HTML5 and HTML5.1. The WHATWG publishes HTML, which is a rough superset of W3C HTML5.1. "Differences from HTML4" describes the differences of the HTML specifications from those of HTML4, and calls out cases where they differ from each other. This document may not provide accurate information, as the specifications are still actively in development. When in doubt, always check the specifications themselves. [HTML5] [HTML5NIGHTLY] [HTML]
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This is the 28 May 2013 W3C Working Draft produced by the HTML Working Group, part of the HTML Activity. The Working Group intends to publish this document as a Working Group Note. The appropriate forum for comments is W3C Bugzilla. (firstname.lastname@example.org, a mailing list with a public archive, is no longer used for tracking comments.)
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This document covers the W3C HTML5 specification, W3C HTML5.1 specification, and the WHATWG HTML standard. For readability, these are referred to as if they were a single specification: "the HTML specification" or simply "HTML" when something applies equally to all of them; otherwise, they are called out explicitly.
HTML has been in continuous evolution since it was introduced to the Internet in the early 1990s. Some features were introduced in specifications; others were introduced in software releases. In some respects, implementations and Web developer practices have converged with each other and with specifications and standards, but in other ways, they have diverged.
The HTML specification reflects an effort, started in 2004, to study contemporary HTML implementations and Web content. The specification:
Defines a single language called HTML which can be written in HTML syntax and in XML syntax.
Defines detailed processing models to foster interoperable implementations.
Improves markup for documents.
Introduces markup and APIs for emerging idioms, such as Web applications.
The contents of HTML, as well as the contents of this document which depend on HTML, are still being discussed on the HTML Working Group and WHATWG mailing lists.
Open issues for WHATWG HTML, see "Issues:" at the top of the specification. The specification also has annotation boxes in the margin which can link to bugs.
Open issues for W3C HTML5 and W3C HTML5.1, see the "Status of This Document" section.
HTML is defined in a way that is backward compatible with the way user agents handle content. To keep the language relatively simple for Web developers, several older elements and attributes are not included, as outlined in the other sections of this document, such as presentational elements that are better handled using CSS.
User agents, however, will always have to support these older
elements and attributes. This is why the HTML specification clearly
separates requirements for Web developers (referred to as "authors" in the
specification) and user agents; for instance, this
means that Web developers cannot use the
isindex or the
plaintext element, but user agents are required to support
them in a way that is compatible with how these elements need to behave
for compatibility with Web content.
Since HTML has separate conformance requirements for Web developers and user agents there is no longer a need for marking features "deprecated".
The HTML4 specification reached Recommendation status before it was completely implemented in user agents. HTML4 still is not completely implemented, because it contains various bugs that have been fixed in the current HTML specification, which user agents are much closer to implementing than HTML4.
The WHATWG HTML standard is under continual development where bugs are fixed and new features are introduced over time. Features can also be removed from the specification if they lack implementor interest, are not being used by Web developers, or for other reasons. The WHATWG does not publish frozen snapshots.
The W3C HTML5 specification is trying to reach Recommendation status. New features are generally not added unless they are implemented by at least two browsers and have tests demonstrating interoperability. Minor bug fixes can be applied. This means that W3C HTML5 may contain bugs that have been fixed in WHATWG HTML or W3C HTML5.1, or both.
The W3C HTML5.1 specification is similar to WHATWG HTML: it is under continual development where bugs are fixed and new features are introduced over time, and features can be removed from the specification for the same reasons as with WHATWG HTML. It cherry-picks changes from the WHATWG HTML standard and also gets direct changes. It is expected to eventually go through the same procedure as W3C HTML5, and then a new version will be minted.
HTML defines a syntax, referred to as "the HTML syntax", that is
mostly compatible with HTML4 and XHTML1 documents published on the
Web, but is not compatible with the more esoteric SGML features of
HTML4, such as
as these are not supported by most user agents. Documents using the HTML
syntax are served with the
HTML also defines detailed parsing rules (including "error
handling") for this syntax which are largely compatible with HTML4-era
implementations. User agents have to use these rules for resources that
text/html media type. Here is an example document
that conforms to the HTML syntax:
<!doctype html> <html> <head> <meta charset="UTF-8"> <title>Example document</title> </head> <body> <p>Example paragraph</p> </body> </html>
The other syntax that can be used for HTML is XML. This syntax
is compatible with XHTML1 documents and implementations. Documents
using this syntax need to be served with an XML media type (such as
application/xml) and elements
need to be put in the
namespace following the rules set forth by the XML specifications.
Below is an example document that conforms to the XML syntax of HTML.
<?xml version="1.0" encoding="UTF-8"?> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Example document</title> </head> <body> <p>Example paragraph</p> </body> </html>
For the HTML syntax, Web developers are required to declare the character encoding. There are three ways to do that:
At the transport level; for instance, by using the HTTP
Using a Unicode Byte Order Mark (BOM) character at the start of the file. This character provides a signature for the encoding used.
meta element with a
attribute that specifies the encoding within the first 1024 bytes of
the document; for instance,
could be used to specify the UTF-8 encoding. This replaces the need
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
although that syntax is still allowed.
For the XML syntax, Web developers have to use the rules as set forth in the XML specification to set the character encoding.
The HTML syntax requires a doctype to be specified to ensure that the browser renders the page in standards mode. The doctype has no other purpose. [DOCTYPE]
The doctype declaration for the HTML syntax is
<!DOCTYPE html> and is
case-insensitive. Doctypes from earlier versions of
HTML were longer because the HTML language was SGML-based and therefore
required a reference to a DTD. This is no longer the case and
the doctype is only needed to enable standards mode for documents
written using the HTML syntax. Browsers already do this for
To support legacy markup generators that cannot generate the preferred
short doctype, the doctype
<!DOCTYPE html SYSTEM
"about:legacy-compat"> is allowed in the HTML syntax.
The strict doctypes for HTML 4.0, HTML 4.01, XHTML 1.0 as well as XHTML 1.1 are also allowed (but are discouraged) in the HTML syntax.
In the XML syntax, any doctype declaration may be used, or it may be omitted altogether. Documents with an XML media type are always handled in standards mode.
The HTML syntax allows for MathML and SVG elements to
be used inside a document. An
tag causes the HTML parser to switch to a special insertion mode which puts
elements and attributes in the appropriate namespaces, does case fixups for
elements and attributes that have mixed case, and supports the empty-element
syntax as in XML. The syntax is still case-insensitive and attributes allow
the same syntax as for HTML elements. Namespace declarations may be omitted.
CDATA sections are supported in this insertion mode.
Some MathML and SVG elements cause the parser to switch back to "HTML
foreignObject, so you can
use HTML elements or a new
For instance, a very simple document using some of the minimal syntax features could look like:
<!doctype html> <title>SVG in text/html</title> <p> A green circle: <svg> <circle r="50" cx="50" cy="50" fill="green"/> </svg> </p>
There are a few other changes in the HTML syntax worthy of mentioning:
⟩ named character references now expand to U+27E8 and U+27E9 (mathematical left/right angle
bracket) instead of U+2329 and U+232A (left/right-pointing angle bracket), respectively.
Many new named character references have been added, including all named character references from MathML.
Void elements (known as "EMPTY" in HTML4) are allowed to have a trailing slash.
The ampersand (
&) may be left unescaped in more
cases compared to HTML4.
Attributes have to be separated by at least one whitespace character.
Attributes with an empty value may be written as just the attribute name omitting the equals sign and the value, even if the attribute is not a boolean attribute. (It is commonly believed that HTML4 allowed the value to be omitted for boolean attributes. Instead, HTML4 allowed using only the attribute value and omitting the attribute name, for enumerated attributes, but this was not supported in browsers.)
Attributes omitting quotes for the value are allowed to use a larger set of characters compared to HTML4.
The HTML parser does not do any normalization of whitespace in attribute values; for instance, leading and trailing whitespace in the
id attribute is not ignored (and thus now invalid), and newline characters can be used in the
value attribute of the
input element without using character
optgroup end tag is now optional.
colgroup start tag is now optional and is inferred by
the HTML parser.
This section is split up in several subsections to more clearly illustrate the various differences from HTML4.
The following elements have been introduced for better structure:
represents an independent piece of content of a document, such as a
blog entry or newspaper article.
can be used as a container for the dominant contents of another element, such as
the main content of the page. In W3C HTML5 and W3C HTML 5.1, only one such element is allowed in a document.
represents a piece of content that is only slightly related to the
rest of the page.
In WHATWG HTML,
represents the header of a section.
represents a group of introductory or navigational aids.
represents a footer for a section and can contain information about
the author, copyright information, etc.
represents a section of the document intended for navigation.
represents a piece of self-contained flow content, typically
referenced as a single unit from the main flow of the document.
<figure> <video src="example.webm" controls></video> <figcaption>Example</figcaption> </figure>
figcaption can be used as caption (it is optional).
Then there are several other new elements:
audio for multimedia content. Both
provide an API so application Web developers can script their own user
interface, but there is also a way to trigger a user interface
provided by the user agent.
elements are used together with these elements if there are multiple
streams available of different types.
embed is used for plugin
mark represents a run of
text in one document marked or highlighted for reference purposes, due
to its relevance in another context.
progress represents a
completion of a task, such as downloading or when performing a series
of expensive operations.
meter represents a
measurement, such as disk usage.
time represents a date
WHATWG HTML and W3C HTML5.1 has
allows content to be annotated with a machine-readable value.
dialog for showing a dialog.
bdi represents a span of
text that is to be isolated from its surroundings for the purposes of
bidirectional text formatting.
wbr represents a line break
canvas is used for rendering
dynamic bitmap graphics on the fly, such as graphs or games.
represents a command the user can invoke from a popup menu.
<input list="browsers"> <datalist id="browsers"> <option value="Safari"> <option value="Internet Explorer"> <option value="Opera"> <option value="Firefox"> </datalist>
represents control for key pair generation.
represents some type of output, such as from a calculation done
type attribute now has the
following new values:
The idea of these new types is that the user agent can provide the user interface, such as a calendar date picker or integration with the user's address book, and submit a defined format to the server. It gives the user a better experience as his input is checked before sending it to the server meaning there is less time to wait for feedback.
Several attributes have been introduced to various elements that were already part of HTML4:
autofocus attribute can be specified on the
input (except when the
type attribute is
button elements. It provides a declarative way to focus a
form control during page load. Using this feature should enhance the
user experience compared to focusing the element with script as the user can turn it off if the user does not like
it, for instance.
<input type=email placeholder="email@example.com">
form attribute for
fieldset elements allows for
controls to be associated with a form. These elements can now be
placed anywhere on a page, not just as descendants of the
form element, and still be associated with a
<table> <tr> <th>Key <th>Value <th>Action <tr> <td><form id=1><input name=1-key></form> <td><input form=1 name=1-value> <td><button form=1 name=1-action value=save>✓</button> <button form=1 name=1-action value=delete>✗</button> ... </table>
required attribute applies to
input (except when the
type attribute is
image or some button type such as
textarea. It indicates that the user
has to fill in a value in order to submit the form. For
select, the first
option element has to be a placeholder with an empty value.
<label>Color: <select name=color required> <option value="">Choose one <option>Red <option>Green <option>Blue </select></label>
fieldset element now allows the
disabled attribute which disables all descendant controls (excluding those that are descendants of the
when specified, and the
name attribute which can be used for script access.
input element has several new attributes to
step. As mentioned before it also has a new
list attribute which can be used together with the
datalist element. It also now has the
height attributes to specify the dimensions of the image when using
button elements have
formtarget as new attributes. If present, they override
target attributes on the
menu element has two new attributes:
allow the element to transform into a menu as found in typical user
interfaces as well as providing for context menus in conjunction with the
link element has a new attribute called
sizes. It can be used in conjunction with the
icon relationship (set through the
attribute; can be used for e.g. favicons) to indicate the size of the
referenced icon, thus allowing for icons of distinct dimensions.
img element has a new attribute called
crossorigin to use CORS in the fetch and if it is successful, allows the image data to be
read with the
canvas API. In WHATWG HTML and W3C HTML5.1, the
script element has a
crossorigin attribute to allow script
errors to be reported to
with information about the error. WHATWG HTML and W3C HTML5.1 also has the
attribute on the
Several attributes from HTML4 now apply to all elements. These
are called global attributes:
title. Additionally, XHTML 1.0
xml:space on some elements, which is now allowed
on all elements in XHTML documents.
There are also several new global attributes:
contenteditable attribute indicates that
the element is an editable area. The user can change the contents of the
element and manipulate the markup.
contextmenu attribute can be used to point
to a context menu provided by the Web developer.
data-* collection of Web developer-defined
attributes. Web developers can define any attribute they want as long as they
prefix it with
data- to avoid clashes with future versions of
HTML. These are intended to be used to store custom data to be consumed by
the Web page or application itself. They are not intended for
data to be consumed by other parties (e.g. user agents).
attribute indicates that an element is not yet, or is no longer, relevant.
spellcheck attribute allows for hinting
whether content can be checked for spelling or not.
translate attribute gives a hint to
translators whether the content should be translated.
HTML also makes all event handler attributes from HTML4, which take the
onevent, global attributes and adds
several new event handler attributes for new events it defines; for
event handler attribute for the
play event which is used by the API for the
media elements (
These elements have slightly modified meanings in HTML to better reflect how they are used on the Web or to make them more useful:
b element now represents a
span of text to which attention is being drawn for utilitarian purposes
without conveying any extra importance and with no implication of an
alternate voice or mood, such as key words in a document abstract, product
names in a review, actionable words in interactive text-driven software,
or an article lede.
cite element now solely
represents 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). Specifically the example in HTML4
where it is used to mark up the name of a person is no longer considered
dl element now represents an
association list of name-value groups, and is no longer said to be
appropriate for dialogue.
hr element now represents a
paragraph-level thematic break.
i element now represents a
span of text in an alternate voice or mood, or otherwise offset from the
normal prose in a manner indicating a different quality of text, such as a
taxonomic designation, a technical term, an idiomatic phrase from another
language, a thought, or a ship name in Western texts.
label element the
browser should no longer move focus from the label to the control unless
such behavior is standard for the underlying platform user
menu element is redefined to
be useful for toolbars and popup menus.
s element now represents
contents that are no longer accurate or no longer relevant.
script element can now be
used for scripts or for custom data blocks.
small element now represents
side comments such as small print.
strong element now
represents importance rather than strong emphasis.
u element now represents a
span of text with an unarticulated, though explicitly rendered,
non-textual annotation, such as labeling the text as being a proper name
in Chinese text (a Chinese proper name mark), or labeling the text as
Several attributes have changed in various ways.
accesskey global attribute now allows multiple
characters to be specified, which the user agent can choose from.
attribute now allows the value
object are no longer allowed to contain
percentages. They are also not allowed to be used to stretch the image to
a different aspect ratio than its intrinsic aspect ratio.
attribute is now allowed to have any value, as long as it is unique, is
not the empty string, and does not contain space characters.
attribute takes the empty string in addition to a valid language
identifier, just like
xml:lang does in XML.
The event handler attributes (e.g.
global attribute now always uses CSS as the styling language.
global attribute now allows negative values which indicate that the
element can receive focus but cannot be tabbed to.
The following attributes are allowed but Web developers are discouraged from using them and instead strongly encouraged to use an alternative solution:
language attribute on
script. It is required to have the value
conflict with the
type attribute. Web developers can simply omit it as
it has no useful function.
The elements in this section are not to be used by Web developers. User
agents will still have to support them and various sections in
HTML define how. E.g. the obsolete
is handled by the parser section.
The following elements are not in HTML because their effect is purely presentational and their function is better handled by CSS:
The following elements are not in HTML because using them damages usability and accessibility:
The following elements are not included because they have not been used often, created confusion, or their function can be handled by other elements:
isindex usage can be replaced by usage of form controls.
noscript element is only conforming in the
HTML syntax. It is not allowed in the XML syntax. This is because in order to not only hide visually but also prevent the content to run scripts, apply style sheets, have submittable form controls, load resources, and so forth, the HTML parser parses the content of the
noscript element as plain text. The same is not possible with an XML parser.
Some attributes from HTML4 are no longer allowed in HTML. The specification defines how user agents should process them in legacy documents, but Web developers are not allowed use them and they will not validate.
HTML has advice on what you can use instead.
In addition, HTML has none of the presentational attributes that were in HTML4 as their functions are better handled by CSS:
The content model is what defines how elements may be nested — what is allowed as children (or descendants) of a certain element.
At a high level, HTML4 had two major categories of elements, "inline"
img, text), and "block-level" (e.g.
table). Some elements did not fit in
Some elements allowed "inline" elements (e.g.
p), some allowed "block-level" elements (e.g.
body), some allowed both (e.g.
div), while other elements did not allow either
category but only allowed other specific elements (e.g.
or did not allow any children at all (e.g.
Notice the difference between an element itself being in a
certain category, and having a content model of a certain category; for
p element is itself a
"block-level" element, but has a content model of "inline".
To make it more confusing, HTML4 had different content model rules in its
Strict, Transitional and Frameset flavors; for instance, in Strict, the
body element allowed only "block-level"
elements, but in Transitional, it allowed both "inline" and "block-level".
To make things more confusing still, CSS uses the terms "block-level element" and "inline-level element" for its visual formatting model, which is related to CSS's 'display' property and has nothing to do with HTML's content model rules.
HTML does not use the terms "block-level" or "inline" as part of its content model rules, to reduce confusion with CSS. However, it has more categories than HTML4, and an element can be part of none of them, one of them, or several of them.
Heading content, e.g.
As a broad change from HTML4, HTML no longer has any element that only
accepts what HTML4 called "block-level" elements; e.g. the
body element now allows flow content. Thus, This is
closer to HTML4 Transitional than HTML4 Strict.
Further changes include:
noscript element was a
"block-level" element in HTML4, but is phrasing content in HTML.
Table elements have to conform to the table model (e.g. two cells are not allowed to overlap).
a element now has a transparent content model (except it does not
allow interactive content descendants), meaning that it has the same
content model as its parent. This means that the
a element can now contain e.g.
div elements, if its parent allows flow
map element also has a
transparent content model. The
element is considered phrasing content if there is a
map element ancestor, which means that they
do not need to be direct children of
HTML has introduced many new APIs and has extended, changed or obsoleted some existing APIs.
HTML introduces a number of APIs that help in creating Web applications. These can be used together with the new elements introduced for applications:
An API for form constraint validation (e.g. the
An API for commands that the user can invoke.
An API that enables offline Web applications, with an application cache.
Editing API in combination with a new global
Drag & drop API in combination with a
An API that exposes the components of the document's URL and allows
scripts to navigate, redirect and reload (the
An API that exposes the session history and allows scripts to
update the document's URL without actually navigating, so that
applications don't need to abuse the fragment component for "Ajax-style"
An API for printing the document (
Window object has been defined.
WHATWG HTML has further APIs that are not in W3C HTML5 but are separate specifications at the W3C:
An API for microdata.
An API for bidirectional client-server communication (
An API for server-to-client data push (
The following features from DOM Level 2 HTML are changed in various ways:
document.title now collapses whitespace on
document.domain is made settable, which
can change the document's effective script origin.
document.open() now either clears the
document (if invoked with two or less arguments), or acts like
window.open() (if invoked with
three or four arguments). In the former case, throws an exception in XML.
document.writeln() throw an exception in
XML. The latter two now support variadic arguments; they can add text to
the document's input stream while it is still being parsed, imply a
document.open(), or be ignored altogether in
now returns all HTML elements with a
name attribute matching
DOM Level 2 HTML had an
HTMLDocument interface that
Document and provided HTML-specific members on
documents. HTML has moved these members to the
Document interface, and extended it in a number
of ways. Since all documents use the
Document interface, the
HTML-specific members are now available on all documents, so they are usable
in e.g. SVG documents as well. It also has several new members:
WHATWG HTML has
getItems() for microdata.
WHATWG HTML and W3C HTML5.1 have
cssElementMap to accompany the CSS
Existing scripts that modified the prototype of
should continue to work because
window.HTMLDocument now returns
Document interface object.
HTMLElement interface has also gained several extensions
dataset is a
convenience feature for handling the
data-* attributes, which are exposed as
camel-cased properties; for instance,
= 'test' sets the
data-foo-bar content attribute on
isContentEditable returns true if the
element is editable.
forceSpellCheck() causes the user agent to check spelling of an element.
All event handler IDL attributes.
Some members were previously defined on
HTMLElement but been moved to the
interface in the DOM standard: [DOM]
id reflects the
id content attribute.
className reflects the
class content attribute.
getElementsByClassName() returns a list of elements with the specified
Some interfaces in DOM Level 2 HTML have been extended.
HTMLFormElement now has a named
getter and an indexed getter.
HTMLSelectElement now has a
namedItem() methods, a setter creator,
labels IDL attributes,
and members for the form constrain validation API:
HTMLInputElement now has the
stepDown(), the form
constraint validation API members,
labels, and members for the text field selection
HTMLAnchorElement now has the
text, and implements the
URLUtils interface which has the members
HTMLAreaElement also have the
relList IDL attribute.
HTMLAreaElement also implements the
In addition, most new content attributes also have corresponding IDL
attributes on the elements' interfaces, e.g. the
sizes IDL attribute on
HTMLLinkElement which reflects the
sizes content attribute.
Some APIs are now either removed altogether, or marked as obsolete.
All IDL attributes that reflect a content attribute that is itself
obsolete, are now also obsolete; for instance, the
bgColor IDL attribute on
HTMLBodyElement which reflects the
content attribute is now obsolete.
The following interfaces are marked obsolete since the elements are
HTMLIsIndexElement interface is removed altogether since
the HTML parser expands an
isindex tag into other elements. The
HTMLBaseFontElement interface is also removed since the element has no effect.
The following members of the
HTMLDocument interface (which
have now moved to
Document) are now
The changelogs in this section indicate what has been changed in WHATWG HTML, W3C HTML5 and W3C HTML5.1 between somewhat arbitrary dates, often close to publications of the W3C HTML5 or W3C HTML5.1 drafts. Rationale for changes can be found in the firstname.lastname@example.org and email@example.com mailing list archives, and the WHATWG Weekly series of blog posts. More fundamental rationale is being collected on the WHATWG Rationale wiki page. Many editorial and minor technical changes are not included in these changelogs. Implementors are strongly encouraged to follow the development of the main specification on a frequent basis so they become aware of all changes that affect them early on.
The changes in the changelogs are in rough reverse chronological order.
The canvas 2d context has a new method
isPointInStroke(). (WHATWG HTML and W3C HTML5.1.)
DataTransferItemList interface (part of drag and drop API) now has a
remove() method instead of a deleter. (WHATWG HTML and W3C HTML5.1.)
registerProtocolHandler() API now supports
geo: schemes. (
bitcoin: is WHATWG HTML only.)
prompt() methods now have all arguments optional. (WHATWG HTML and W3C HTML5.1.)
fieldset element can now match the
:invalid pseudo-class. (WHATWG HTML and W3C HTML5.1.)
HTMLBaseFontElement interface has been removed. (WHATWG HTML and W3C HTML5.1.)
The specification has integrated with the URL standard which effectively added the
query IDL attributes to the
area elements and the
location object. (WHATWG HTML and W3C HTML5.1.)
hgroup element has been dropped. (W3C HTML5 and W3C HTML5.1.)
The HTML parser now better supports
innerHTML on non-HTML elements. (WHATWG HTML and W3C HTML5.1.)
Various things that were present in WHATWG HTML but missing in W3C HTML5.1 were "un-forked": The
download attribute on
area, the application cache prefer-online feature, the text range API on
cssElementMap IDL attribute on
Document, various bits for microdata. (W3C HTML5.1 only.)
The drag and drop API now has a
dragexit event. (WHATWG HTML and W3C HTML5.1.)
form element now recieves an
invalid event when submission fails due to form validation (in addition to the individual controls). (WHATWG HTML and W3C HTML5.1.)
navigator object now has a
product IDL attribute that always returns "Gecko" (for compatibility). (WHATWG HTML and W3C HTML5.1.)
datetime IDL attribute got renamed to
dateTime. (WHATWG HTML and W3C HTML5.1.)
replaceState() methods can now be invoked with
null as the third argument.
main element has been added.
stepDown() methods on the
input element have been tweaked. (WHATWG HTML and W3C HTML5.1.)
img element now supports progress events. (WHATWG HTML and W3C HTML5.1.)
fillRule IDL attribute has been added to the canvas 2d context. (WHATWG HTML only.)
style IDL attribute on HTML elements is now settable. (WHATWG HTML and W3C HTML5.1.)
media attribute has been dropped from the
area elements. (WHATWG HTML and W3C HTML5.1.)
Heading elements now support automatic sizing in
hgroup if they follow an
h1 element. (WHATWG HTML only.)
navigator object now has a
language IDL attribute. (WHATWG HTML and W3C HTML5.1.)
menu API has been revamped. The
command element was dropped. An new
menuitem element was added. The
type attribute now uses the value "
popup" instead of "
button element has a new
menu attribute and the
type attribute supports a new value "
menu". (WHATWG HTML and W3C HTML5.1.)
table element now supports sorting columns. The
table element has a new
sortable attribute and a
stopSorting() method. The
th element has a new
sorted attribute and a
sort() method. (WHATWG HTML and W3C HTML5.1.)
autocomplete attribute on form controls now supports the
cc-type type. (WHATWG HTML and W3C HTML5.1.)
currentScript IDL attribute on
document was added. (WHATWG HTML and W3C HTML5.1.)
script elements now support the
crossorigin attribute. (WHATWG HTML and W3C HTML5.1.)
canvas element now supports indirect and proxied rendering contexts, to support drawing from a worker. The
ImageBitmap interfaces are introduced, the
canvas element has new
transferControlToProxy() methods, and a new
createImageBitmap() method on
window was introduced. (WHATWG HTML and W3C HTML5.1.)
The canvas 2d context has a new
direction IDL attribute. (WHATWG HTML only.)
screen object has a new
canvasResolution IDL attribute. (WHATWG HTML only.)
PortCollection() constructor was added to support sending messages to many ports while allowing them to be garbage collected. (WHATWG HTML only.)
getItem() method on
Storage can now return null. (WHATWG HTML only.)
sandbox attribute on
iframe supports a new value "
allow-pointer-lock". (WHATWG HTML and W3C HTML5.1.)
The HTML parser now invokes mutation observers. (WHATWG HTML and W3C HTML5.1.)
canvas element has a new
supportsContext() method. (WHATWG HTML and W3C HTML5.1.)
abbr attribute on the
th element is now conforming.
forceSpellCheck() method on HTML elements was added. (WHATWG HTML and W3C HTML5.1.)
EventSource API now reconnects for DNS errors and TCP-level connection failures. (WHATWG HTML only.)
fastSeek() method was added to media elements. (WHATWG HTML and W3C HTML5.1.)
https+aes: schemes were removed due to lack of interest. (WHATWG HTML only.)
rel=noreferrer now does not clone the
error event for
Worker objects now has a
column IDL attribute. (WHATWG HTML only.)
autofocus attribute on form controls in
dialog elements now has an effect when the
showModal() method is invoked.
The content model for
ruby was changed with regards to nested
script tags in the HTML syntax now execute.
The placeholder section for the
find() API has been dropped.
An encoding declaration is now required in the HTML syntax even if only ASCII characters are used.
Some bug fixes in the Drag and Drop API.
inBandMetadataTrackDispatchType IDL attribute was added to
TextTrackCue() constructor now has fewer arguments.
accept attribute now supports file extensions as well as MIME types.
initialTime IDL attribute on media elements has been dropped.
startOffsetTime IDL attribute on media elements has been renamed to
Further changes to WHATWG HTML that do not affect W3C HTML5:
Several changes and bug fixes in the Text Track API.
addElement() was dropped from the Drag and Drop API.
Media queries are now proxied for
iframe elements with the
:disabled pseudo-classes now apply to
input elements in the Hidden state.
magnet schemes are now in the
table elements now have 'box-sizing:border-box' by default.
Bug fixes in the "potentially CORS-enabled fetch" algorithm.
The document outline algorithm now ignores elements with the
Markup generators that are unable to provide required
alt text can now use a specific attribute on
img that makes validators ignore the missing
Workers and shared workers now support
inputmode attribute has been added to
autocomplete attribute has been extended to support prefilling specific things.
WebSocket supports sending
ArrayBufferView as well as
border attribute on
table is non-conforming again.
The canvas ImageData methods now assume 96dpi, and a set of "HD" methods have been introduced.
The shared worker
connect event now also exposes the source port in the
source IDL attribute.
Lone surrogates are converted to U+FFFD instead of throwing in WebSocket
setRangeText() method has been added to
srcset attribute has been added to
Application cache now has an
Dialogs are now supported with the
dialog element, the
inert global attribute and the
dialog method on
currentTransform IDL attribute, several IDL attributes for font metrics,
imageSmoothingEnabled IDL attribute,
removeHitRegion() method, support for dashed lines, have been added to the canvas 2d context.
Support for mutation observers was added.
direction were renamed to
command element now has a
Drag and drop content is now suggested to be filtered by user agents to prevent XSS attacks.
translate global attribute was added.
prompt() methods are now allowed to do nothing during
script element now supports
window.onerror now supports a fourth argument for column position.
window.opener IDL attribute can now return null in some cases.
clearInterval() methods were made synonymous.
@global at-rule was introduced, for use together with
style elements with the
object elements now have a legacy caller.
The handling of
window.onerror's return value was changed to match reality.
setTimeout() API is now allowed to be throttled in background tabs.
:invalid pseudo-classes now apply to
toBlob() method on
canvas now honors the origin-clean flag.
activeElement IDL attribute now points to the relevant browsing context container (e.g.
iframe) when a child document has focus.
atob() method now ignores whitespace.
dropzone attribute was changed to use "
string:" and "
file:" instead of "
s:" and "
The HTML parser was fixed to correctly handle a case involving foreign lands and foster parenting.
The date-and-time microsyntaxes now allows a single space instead of a "T".
Application cache no longer checks the MIME type of the cache manifest.
cueAsSource IDL attribute on
TextTrackCue got renamed to
window.onerror API is now invoked with dummy arguments for cross-origin scripts.
textLength IDL attributes have their newlines normalized to LF.
q element now has language-specific quotes rendered by default.
data element was introduced.
time element was redesigned to make it match how people wanted to use it. Its
pubdate attribute was dropped.
The legacy caller on
form was removed.
location.resolveURL() method was removed.
track element now sniffs instead of obeying the MIME type.
load() method on documents created by
createDocument() is now defined on the
HTMLDocument moved to
window.HTMLDocument now just returns
TextTrack interfaces were merged and
TextTrackCue was made more mutable.
selectedOption IDL attribute on
input was dropped.
Attribute values in Selectors are now case sensitive for all attributes.
readyState IDL attribute moved from
text/html-sandboxed MIME type was dropped.
Floating point numbers are now allowed to begin with a "
Navigating to an audio or video resource is now supported.
Table cells now allow flow content but does not allow
footer, sectioning content or heading content descendants.
Adding a track to a media element now fires an
addtrack event on the relevant track list objects.
currentTime on media elements before the media has loaded now defers the seek instead of throwing.
Plugins are no longer disabled in sandboxed
iframes if they honor the
Some tweaks to history navigation and related events.
Media elements and
MediaControllers now get paused when they end.
Events now support constructors and some
init*Event() methods were removed.
Media elements now fire a
suspend event when the resource is loaded.
Form submission now normalizes newlines to CRLF.
Some tweaks around bidi and the
Large parts of the Editing section moved to HTML Editing APIs.
UndoManager and related features moved to UndoManager and DOM Transaction.
unregisterContentHandler() were added.
registerContentHandler() now has a blacklist of MIME types.
registerProtocolHandler() now has a whitelist of protocols, but also supports any protocol that starts with "
Fragment identifiers for
text/html resources now don't need to point to an element with a matching ID.
audio elements are now allowed to have zero
There are now some restrictions on the use of bidi formatting characters.
size attributes are allowed (but give warnings in validators) on
input elements with
The link relation "
shortcut icon" is now allowed.
Heading elements are now allowed to have the
Things that use
EventTarget now inherit from it instead of using "implements".
setInterval() API now clamps to 4ms instead of 10ms.
select element and its
options collection now have a setter.
rel=help on links now show a help cursor by default.
window.print() before the document is loaded defers the print until it is loaded.
Application cache gained an
createHTMLDocument(), HTML-specific overrides to some DOM Core features (like
createElement()), some definitions, the
id IDL attribute and ID handling moved to DOM4.
Fragment identifiers can now survive redirects.
replaceState() methods now change the history entry to GET.
The command API now has its properties prefixed so they are now
The structured clone algorithm now supports sparse arrays.
window.postMessage now supports transferring some objects instead of cloning them, and supports transferring
Application cache was made stricter in its MIME type checking.
placeholder attribute is now allowed on
input elements with
MediaController gained an
onended event listener.
The HTML parser changed its handling of U+0000 characters in some places.
object element gained a new attribute
typemustmatch, to make it safer for Web developers to embed untrusted resources where they expect a certain content type.
form attribute was removed from
The HTML parser was made more forward compatible in its handling of
Some MIME types (e.g.
text/plain) that are guaranteed to never be supported as scripting types for
script were specified, so Web developers can safely use them for custom data blocks.
about:blank documents created from
window.open() now get a
window.status was specified to exist but do nothing.
Drag and drop
DataTransferItems was renamed to
Application cache now supports 'no-store' and HTTPS.
The structured clone algorithm now supports getters.
crossorigin attribute has been added to
audio to use CORS.
external IDL attribute has been added on
window and has the members
Further changes to WHATWG HTML that do not affect W3C HTML5:
The 2d context now supports ellipses with the
arcTo() methods and the new
The 2d context now supports
Path objects. SVG path data can be added to a
https+aes: URL schemes were added to allow sensitive resources to be held on untrusted servers.
itemprop attribute is used on an element where microdata gets its value from an attribute (like
a elements), that attribute is now required.
PeerConnection was moved to WebRTC.
WebVTT was moved to its own specification.
WebSockets no longer receive messages in the
The Atom conversion algorithm was dropped.
itemtype attribute now allows multiple types.
CanvasPixelArray was dropped in favor of
The microdata to RDF conversion algorithm was dropped.
link element is no longer allowed to have both
WebSocket API disallows opening an insecure connection if the document uses a secure connection.
The "storage mutex" is made optional.
Web Storage no longer supports structured data.
a element got a new
download attribute. This attribute is not included in W3C HTML5.
An experimental specification for the
window.find() method was added.
The 2d context
strokeText() methods now do not collapse whitespace.
Microdata now handles infinite loops.
location now stringifies.
Script errors in a Web Worker can now be detected in a parent worker or the document with the
EventSource now supports CORS.
EventSource was made stricter in its MIME type checking.
Web Workers gained the
Web Workers gained the
onoffline event handlers.
WebSockets API has the
error event again.
WebSockets API now exposes the selected extensions.
Various tweaks to the UDP
WebSocket close code and reason are now supported in the API.
Binary data is now supported in WebSockets.
Redirects in WebSockets are now blocked for security reasons.
Support for the
object, CSS, etc, has been dropped.
toBlob() method has been added to
drawFocusRing() method on the
canvas 2d context has been split into two methods,
values attribute on
PropertyNodeList has been replaced with a
select event has been specified.
selectDirection IDL attribute has been added to
:disabled pseudo-classes now match
fieldset, and the
:indeterminate pseudo-class can now match
getKind() method has been added to
MediaController API and the
mediagroup attribute have been added to synchronize playback of media elements.
Some ARIA defaults have changed, and it is now invalid to specify ARIA attributes that match the defaults.
getName() method on
TrackList was renamed to
border attribute on
table is now conforming.
u element is now conforming.
summary attribute on
table is now non-conforming.
audio attribute on
video was changed to a boolean
Content-Language meta pragma is now non-conforming.
replaceState features have
been changed based on implementation feedback in Firefox, and
has been introduced.
tracks IDL attribute on media elements has been renamed
formchange events, and
methods have been dropped.
first and related synonyms
have been dropped.
Removing a media element from the DOM and inserting it again in the same script now doesn't pause the media element.
video element's letterboxing rules are now specified in
terms of CSS 'object-fit'.
Cross-origin fonts now don't leak information about the font when drawn
The character encoding declaration is now allowed to be within the first 1024 bytes instead of the first 512 bytes.
onerror event handler on
window is now invoked
for compile-time script errors as well as runtime errors.
script elements now have
true, which can be set to
false to make
the scripts execute in insertion order.
btoa() methods have been specified.
The suggested file extension for application cache manifest files has been
formaction attributes are
no longer allowed to have the empty string as value.
Drag and drop model was refined.
A new global
dropzone attribute was added.
bdi element was added to aid with user-generated
content that may have bidi implications.
dir attribute gained a new "
dirname attribute was added to
elements. When specified the directionality as specified by the user
will be submitted to the server as well.
track element and associated TextTrack API were added for video text tracks.
type attribute on the
ol element is now allowed.
getSelection() API moved to a separate
DOM Range draft.
UndoManager has been removed from the W3C copy of
HTML5 for now as it is not ready yet.
Numerous changes to the HTML parsing algorithm based on implementation feedback.
hidden attribute now works for table-related
getContext() method is now
defined to be able to handle multiple contexts better.
The media elements'
startTime IDL attribute was
prefetch link relationship can now be used on
datetime attribute of
del no longer requires a time to be specified.
Using PUT and DELETE as HTTP methods for the
element is no longer supported.
s element is no longer deprecated.
video element has a new
Per usual, lots of other minor fixes have been made as well.
ping attribute has been removed from the W3C
version of HTML5.
title element is optional for
srcdoc documents and other scenarios
where a title is already available. As is the case with email.
keywords is now a standard metadata name for the
allow-top-navigation value has been added for the
sandbox attribute on the
iframe element. It
allows the embedded content to navigate its parent when specified.
wbr element has been added.
alternate keyword for the
attribute of the
link element can now be used to point to
feeds again, even if the feed is not an alternative for the
The HTML to Atom mapping has been removed from the W3C version of HTML5.
In addition lots of minor changes, clarifications, and fixes have been made to the document.
dialog element has been removed. A section with
advice on how to mark up conversations has effectively replaced
document.head has been introduced to provide
convenient access to the
head element from script.
The link type
feed has been removed.
alternate with specific media types
is to be used instead.
createHTMLDocument() has been introduced as API to
allow easy creation of HTML documents.
progress elements no
longer have "magic" processing of their contents because it could not
be made to work internationally.
progress elements, as well
output element, can now be labeled using the
A new media type,
text/html-sandboxed, was introduced
to allow hosting of potentially hostile content without it causing
srcdoc attribute for the
was introduced to allow embedding of potentially hostile content
inline. It is expected to be used together with the
figure element now uses a new element
figcaption rather than
legend because people
want to use HTML long before it reaches W3C Recommendation.
details element now uses a new element
summary for exactly the same reason.
autobuffer attribute on media elements was renamed
A whole lot of other smaller issues have also been resolved. The above list summarizes what is thought to be of primary interest to Web developers.
In addition to all of the above, Microdata, the 2D context API for
canvas, and Web Messaging (
have been split into their own drafts at the W3C (the WHATWG still
publishes a version of HTML that includes them):
Specific microdata vocabularies are gone altogether in the W3C draft of HTML5 and are not published as a separate draft. The WHATWG draft of HTML still includes them.
time element is empty user agents have to
render the time in a locale-specific manner.
load event is dispatched at
but now has
Document as its target.
pushState() now affects the
onredo are now on
Media elements now have a
startTime member that
indicates where the current resource starts.
header has been renamed to
hgroup and a
header element has been introduced.
createImageData() now also takes
createPattern() can now take a
element as argument too.
footer element is no longer allowed in
header is not allowed in
A new control has been introduced:
The Command API now works for all elements.
accesskey is now properly defined.
article now take a
A new feature called Microdata has been introduced which allows people to embed custom data structures in their HTML documents.
Using the Microdata model three predefined vocabularies have also been included: vCard, vEvent, and a model for licensing.
Drag and drop has been updated to work with the Microdata model.
The last of the parsing quirks has been defined.
textLength has been added as member of the
rp element now takes phrasing content rather than
a single character.
location.reload() is now defined.
hashchange event now fires asynchronously.
Rules for compatibility with XPath 1.0 and XSLT 1.0 have been added.
spellcheck IDL attribute now maps to a
hasFeature() support has been reduced to a
Audio() constructor sets the
td element is no longer allowed in
input element and
now have a
files IDL attribute.
bb have been removed due
to their design not being agreed upon.
The cue range API has been removed from the media elements.
Support for WAI-ARIA has been integrated.
On top of this list quite a few minor clarifications, typos, issues specific to implementors, and other small problems have been resolved.
In addition, the following parts of HTML have been taken out and will likely be further developed at the IETF:
Definition of URLs.
Definition of Content-Type sniffing.
A new global attribute called
spellcheck has been
this in the global object
WindowProxy object rather than the
value IDL attribute for
elements in the File Upload state is now defined.
designMode was changed to be more in
line with legacy implementations.
drawImage() method of the 2D drawing API can now
video element as well.
The way media elements load resources has been changed.
document.domain is now IPv6-compatible.
video element gained an
boolean attribute that serves as a hint.
You are now allowed to specify the
meta element with a
charset attribute in XML documents if the value of that
attribute matches the encoding of the document. (Note that it does not
specify the value, it is just a talisman.)
members of media elements have been removed.
The media element resource selection algorithm is now asynchronous.
postMessage() API now takes an array of
MessagePort objects rather than just one.
The second argument of the
add() method on the
select element and the
options member of the
select element is now optional.
target attributes on
button elements have been
A "storage mutex" concept has been added to deal with separate
pages trying to change a storage object (
localStorage) at the same time. The
Navigator gained a
to allow it to be explicitly released.
A syntax for SVG similar to MathML is now defined so that SVG can
be included in
placeholder attribute has been added to
keygen element for key pair generation.
datagrid element was revised to make the API more
asynchronous and allow for unloaded parts of the grid.
In addition, several parts of HTML have been taken out and will be further developed by the Web Applications Working Group as standalone specifications:
Web Storage (
data member of
ImageData objects has
been changed from an array to a
Shadows are now required from implementations of the
canvas element and its API.
Security model for
canvas is clarified.
Various changes to the processing model of
been made in response to implementation and Web developer feedback. E.g.
clarifying what happens when NaN and Infinity are passed and fixing the
innerHTML in XML was slightly changed to improve
toDataURL() method on the
element now supports setting a quality level when the media type
poster attribute of the
now affects its intrinsic dimensions.
The behavior of the
type attribute of the
link element has been clarified.
Sniffing is now allowed for
link when the expected
type is an image.
A section on URLs is introduced dealing with how URL values are to be interpreted and what exactly Web developers are required to do. Every feature of the specification that uses URLs has been reworded to take the new URL section into account.
It is now explicit that the
href attribute of the
base element does not depend on
It is now defined what the behavior should be when the base URL changes.
URL decomposition IDL attributes are now more aligned with Internet Explorer.
xmlns attribute with the value
http://www.w3.org/1999/xhtml is now allowed on all HTML
data-* attributes and custom attributes on
embed element now have to match the XML
Name production and cannot contain a colon.
WebSocket API is introduced for bidirectional communication with a server.
The default value of
volume on media elements is now
1.0 rather than 0.5.
event-source was renamed to
because no other HTML element uses a hyphen.
A message channel API has been introduced augmenting
A new element named
bb has been added. It represents a
user agent command that the user can invoke.
addCueRange() method on media elements has been
modified to take an identifier which is exposed in the callbacks.
It is now defined how to mutate a DOM into an infoset.
parent attribute of the
is now defined.
embed element is defined to do extension sniffing
for compatibility with servers that deliver Flash as
text/plain. (This is marked as an issue in the
specification to figure out if there is a better way to make this
embed can now be used without its
getElementsByClassName() is defined to be ASCII
case-insensitive in quirks mode for consistency with CSS.
In HTML documents
localName no longer returns the node
name in uppercase.
data-* attributes are defined to be always
opener attribute of the
is not to be present when the page was opened from a link with
top attribute of the
Window object is
a element now allows nested flow content, but not
nested interactive content.
It is now defined what the
header element means to
document summaries and table of contents.
What it means to fetch a resource is now defined.
Patterns are now required for the
autosubmit attribute has been removed from the
insertAdjacentHTML() has been added.
xml:lang is now allowed in HTML when
is also specified and they have the same value. In XML
lang is allowed if
xml:lang is also specified
and they have the same value.
frameElement attribute of the
object is now defined.
An event loop and task queue is now defined detailing script execution and events. All features have been updated to be defined in terms of this mechanism.
alt attribute is omitted a
attribute, an enclosing
figure element with a
legend element descendant, or an
enclosing section with an associated heading must be present.
irrelevant attribute has been renamed to
definitionURL attribute of MathML is now properly
supported. Previously it would have ended up being all lowercase during
User agents must treat US-ASCII as Windows-1252 for compatibility reasons.
An alternative syntax for the DOCTYPE is allowed for compatibility with some XML tools.
Data templates have been removed (consisted of the
The media elements now support just a single
load() method on media elements has been
redefined as asynchronous. It also tries out files in turn now rather
than just looking at the
type attribute of the
A new member called
canPlayType() has been added to
the media elements.
attributes have been removed from the media elements.
Location object gained a
q element has changed again. Punctuation is to be
provided by the user agent again.
Various changes were made to the HTML parser algorithm to be more in line with the behavior Web sites require.
beforeunload events are
The IDL blocks in the specification have been revamped to be in line with the upcoming Web IDL specification.
Table headers can now have headers. User agents are required to
headers attribute pointing to a
th element, but Web developers are required to only let them
Interested parties can now register new
meta element has a
attribute it must occur within the first 512 bytes.
StorageEvent object now has a
It is now defined how HTML is to be used within the SVG
The notification API has been dropped.
How [[Get]] works for the
Window objects is now defined.
Window object gained the
toolbar attributes giving
information about the user interface.
The application cache section has been significantly revised and updated.
document.domain now relies on the Public Suffix List.
A non-normative rendering section has been added that describes user agent rendering rules for both obsolete and conforming elements.
Web Forms 2.0, previously a standalone specification, has been fully integrated into HTML since last publication. The following changes were made to the forms chapter:
Support for XML submission has been removed.
Support for form filling has been removed.
Support for filling of the
datalist elements through the
has been removed.
Support for associating a field with multiple forms has been
removed. A field can still be associated with a form it is not nested
in through the
dispatchFormChange() methods have been removed from the
Repetition templates have been removed.
inputmode attribute has been removed.
input element in the File Upload state no longer
allow attribute on
input elements in
the File Upload state is no longer authoritative.
accept attributes for
textarea have been removed.
RFC 3106 is no longer explicitly supported.
submit() method now just submits, it no longer
ensures the form controls are valid.
input element in the Range state now defaults to
the middle, rather than the minimum value.
size attribute on the
is now conforming (rather than deprecated).
object elements now partake in form submission.
type attribute of the
gained the values
input element gained a
attribute which allows for either multiple e-mails or multiple files to
be uploaded depending on the value of the
elements now have a
novalidate attribute to indicate that
the form fields should not be required to have valid values upon
label element contains an
it may still have a
for attribute as long as it points to
input element it contains.
input element now has an
indeterminate IDL attribute.
input element gained a
Implementation and authoring details around the
attribute have changed.
<meta http-equiv=content-type> is now a
conforming way to set the character encoding.
API for the
canvas element has been cleaned up. Text
support has been added.
globalStorage is now restricted to the same-origin
policy and renamed to
localStorage. Related event
dispatching has been clarified.
postMessage() API changed. Only the origin of the
message is exposed, no longer the URL. It also requires a second
argument that indicates the origin of the target document.
Drag and drop API has got clarification. The
dataTransfer object now has a
attribute indicating the type of data being transferred.
m element is now called
Server-sent events has changed and gotten clarification. It uses a new format so that older implementations are not broken.
figure element no longer requires a caption.
ol element has a new
Character encoding detection has changed in response to feedback.
Various changes have been made to the HTML parser section in response to implementation feedback.
Various changes to the editing section have been made, including
queryCommandEnabled() and related methods.
headers attribute has been added for
table element has a new
MathML support has been added to the HTML parser section. (SVG support is still awaiting input from the SVG WG.)
Web developer-defined attributes have been added. Web developers can add
attributes to elements in the form of
data-name and can access these through the DOM
dataset[name] on the element in question.
q element has changed to require punctuation
inside rather than having the browser render it.
target attribute can now have the value
showModalDialog API has been added.
document.domain API has been defined.
source element now has a new
pixelratio attribute useful for videos that have some kind
bufferingThrottled IDL attributes have been added to the
begin event has been renamed to
loadstart for consistency with the Progress Events
charset attribute has been added to
iframe element has gained the
seamless attributes which provide sandboxing
elements have been added to support ruby annotation.
showNotification() method has been added to show
notification messages to the user.
events has been added.
The editors would like to thank Ben Millard, Bruce Lawson, Cameron McCormack, Charles McCathieNevile, Dan Connolly, David Håsäther, Dennis German, Frank Ellermann, Frank Palinkas, Futomi Hatano, Gordon P. Hemsley, Henri Sivonen, James Graham, Jens Meiert, Jeremy Keith, Jukka K. Korpela, Jürgen Jeka, Krijn Hoetmer, Leif Halvard Silli, Maciej Stachowiak, Mallory van Achterberg, Marcos Caceres, Mark Pilgrim, Martijn Wargers, Martin Leese, Martyn Haigh, Masataka Yakura, Michael Smith, Mike Taylor, Ms2ger, Olivier Gendrin, Øistein E. Andersen, Philip Jägenstedt, Philip Taylor, Randy Peterman, Steve Faulkner, Toby Inkster, Xaxio Brandish, and Yngve Spjeld Landro for their contributions to this document as well as to all the people who have contributed to HTML over the years for improving the Web!