Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
HTML is the core language of the World Wide Web. The W3C publishes HTML5, which is the fifth major revision of HTML. The WHATWG publishes HTML, which is a rough superset of HTML5. "HTML5 differences from HTML4" describes the differences of these documents from HTML4, and calls out cases where HTML is different from HTML5. This document may not provide accurate information as the specifications are still actively in development. When in doubt, always check the specifications themselves. [HTML5][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 5 October 2012 Editor's 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 to accompany the HTML5 specification. The appropriate forum for comments is W3C Bugzilla. (public-html-comments@w3.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.
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 author practices have converged with each other and with specifications and standards, but in other ways, they have diverged.
HTML4 became a W3C Recommendation in 1997. While it continues to serve as a rough guide to many of the core features of HTML, it does not provide enough information to build implementations that interoperate with each other and, more importantly, with a critical mass of deployed content. The same goes for XHTML1, which defines an XML serialization for HTML4, and DOM Level 2 HTML, which defines JavaScript APIs for both HTML and XHTML. HTML5 will replace these documents. [DOM2HTML][HTML4][XHTML1]
The HTML5 draft reflects an effort, started in 2004, to study contemporary HTML implementations and deployed content. The draft:
HTML5 is still a draft. The contents of HTML5, as well as the contents of this document which depend on HTML5, are still being discussed on the HTML Working Group and WHATWG mailing lists. The open issues are linked from the HTML5 draft.
HTML5 is defined in a way that it is backwards compatible with the way user agents handle deployed content. To keep the authoring language relatively simple for authors, several elements and attributes are not included, as outlined in the other sections of this document, such as presentational elements that are better dealt with using CSS.
User agents, however, will always have to support these older elements and attributes and this is why the HTML5 specification clearly separates requirements for authors and user agents. For instance, this means that authors 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 deployed content.
Since HTML5 has separate conformance requirements for authors and user agents there is no longer a need for marking features "deprecated".
The HTML5 specification will not be considered finished before there are at least two complete implementations of the specification. A test suite will be used to measure completeness of the implementations. This approach differs from previous versions of HTML, where the final specification would typically be approved by a committee before being actually implemented. The goal of this change is to ensure that the specification is implementable, and usable by authors once it is finished.
HTML5 defines an HTML syntax that is compatible with HTML4 and XHTML1 documents published on the Web, but is not compatible with the more esoteric SGML features of HTML4, such as processing instructions and shorthand markup as these are not supported by most user agents. Documents using the HTML syntax are served with the text/html
media type.
HTML5 also defines detailed parsing rules (including "error handling") for this syntax which are largely compatible with HTML4-era implementations. User agents must use these rules for resources that have the 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 HTML5 is XML. This syntax is compatible with XHTML1 documents and implementations. Documents using this syntax need to be served with an XML media type and elements need to be put in the http://www.w3.org/1999/xhtml
namespace following the rules set forth by the XML specifications. [XML]
Below is an example document that conforms to the XML syntax of HTML5. Note that XML documents must be served with an XML media type such as application/xhtml+xml
or application/xml
.
<?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, authors are required to declare the character encoding. There are three ways to do that:
Content-Type
header for instance.meta
element with a charset
attribute that specifies the encoding within the first 1024 bytes of the document. For instance, <meta charset="UTF-8">
could be used to specify the UTF-8 encoding. This replaces the need for <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
although that syntax is still allowed.For the XML syntax, authors have to use the rules as set forth in the XML specifications to set the character encoding.
The HTML syntax of HTML5 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. With HTML5 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 <!DOCTYPE html>
.
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 of HTML5 allows for MathML and SVG elements to be used inside a document. An math
or svg
start 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 mode", e.g. mtext
and foreignObject
, so you can use HTML elements or a new math
or svg
element.
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:
The ⟨
and ⟩
named character references now expand to U+27E8 and U+27E9 instead of U+2329 and U+232A, respectively.
Many new named character references have been added, including all from MathML.
Void elements (known as "EMPTY" in HTML4) are allowed to have a trailing slash.
The ampersand (&
) may be left unescaped in some 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 it's not a boolean attribute. (HTML4 actually 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 optgroup
end tag is now optional.
The 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 there are between HTML4 and HTML5.
The following elements have been introduced for better structure:
section
represents a generic document or application section. It can be used together with the h1
, h2
, h3
, h4
, h5
, and h6
elements to indicate the document structure.
article
represents an independent piece of content of a document, such as a blog entry or newspaper article.
aside
represents a piece of content that is only slightly related to the rest of the page.
hgroup
represents the header of a section.
header
represents a group of introductory or navigational aids.
footer
represents a footer for a section and can contain information about the author, copyright information, etc.
nav
represents a section of the document intended for navigation.
figure
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:
video
and audio
for multimedia content. Both provide an API so application authors can script their own user interface, but there is also a way to trigger a user interface provided by the user agent. source
elements are used together with these elements if there are multiple streams available of different types.
embed
is used for plugin content.
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 and/or time.
WHATWG HTML has data
which allows content to be annotated with a machine-readable value.
WHATWG HTML has 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 opportunity.
canvas
is used for rendering dynamic bitmap graphics on the fly, such as graphs or games.
command
represents a command the user can invoke.
details
represents additional information or controls which the user can obtain on demand. The summary
element provides its summary, legend, or caption.
datalist
together with the a new list
attribute for input
can be used to make comboboxes:
<input list="browsers"> <datalist id="browsers"> <option value="Safari"> <option value="Internet Explorer"> <option value="Opera"> <option value="Firefox"> </datalist>
keygen
represents control for key pair generation.
output
represents some type of output, such as from a calculation done through scripting.
The input
element's 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:
The a
and area
elements now have a media
attribute for consistency with the link
element. WHATWG HTML also has the download
and ping
attributes.
The area
element, for consistency with the a
and link
elements, now also has the hreflang
, type
and rel
attributes.
The base
element can now have a target
attribute as well, mainly for consistency with the a
element. (This is already widely supported.)
The meta
element has a charset
attribute now as this was already widely supported and provides a nice way to specify the character encoding for the document.
A new autofocus
attribute can be specified on the input
(except when the type
attribute is hidden
), select
, textarea
and 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.
A new placeholder
attribute can be specified on the input
and textarea
elements. It represents a hint intended to aid the user with data entry.
<input type=email placeholder="a@b.com">
The new form
attribute for input
, output
, select
, textarea
, button
, label
, object
and 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 form
.
<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>
The new required
attribute applies to input
(except when the type
attribute is hidden
, image
or some button type such as submit
), select
and 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>
The fieldset
element now allows the disabled
attribute which disables all descendant controls (excluding those that are descendants of the legend
element) when specified, and the name
attribute which can be used for script access.
The input
element has several new attributes to specify constraints: autocomplete
, min
, max
, multiple
, pattern
and 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 width
and height
attributes to specify the dimensions of the image when using type=image
.
The input
and textarea
elements have a new attribute named dirname
that causes the directionality of the control as set by the user to be submitted as well.
The textarea
element also has two new attributes, maxlength
and wrap
which control max input length and submitted line wrapping behavior, respectively.
The form
element has a novalidate
attribute that can be used to disable form validation submission (i.e. the form can always be submitted).
The input
and button
elements have formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
as new attributes. If present, they override the action
, enctype
, method
, novalidate
, and target
attributes on the form
element.
In WHATWG HTML, the input
and textarea
have an inputmode
attribute.
The menu
element has two new attributes: type
and label
. They 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 global contextmenu
attribute.
The style
element has a new scoped
attribute which can be used to enable scoped style sheets. Style rules within such a style
element only apply to the local tree.
The script
element has a new attribute called async
that influences script loading and execution.
The html
element has a new attribute called manifest
that points to an application cache manifest used in conjunction with the API for offline Web applications.
The link
element has a new attribute called sizes
. It can be used in conjunction with the icon
relationship (set through the rel
attribute; can be used for e.g. favicons) to indicate the size of the referenced icon. Thus allowing for icons of distinct dimensions.
The ol
element has a new attribute called reversed
. When present, it indicates that the list order is descending.
The iframe
element has three new attributes called sandbox
, seamless
, and srcdoc
which allow for sandboxing content, e.g. blog comments.
The object
element has a new attribute called typemustmatch
which allows safer embedding of external resources.
The 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, there is also a new attribute called srcset
to support multiple images for different resolutions and different images for different viewport sizes.
Several attributes from HTML4 now apply to all elements. These are called global attributes: accesskey
, class
, dir
, id
, lang
, style
, tabindex
and title
. Additionally, XHTML 1.0 only allowed xml:space
on some elements, which is now allowed on all elements in XHTML documents.
There are also several new global attributes:
The contenteditable
attribute indicates that the element is an editable area. The user can change the contents of the element and manipulate the markup.
The contextmenu
attribute can be used to point to a context menu provided by the author.
The data-*
collection of author-defined attributes. Authors 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).
The draggable
and dropzone
attributes can be used together with the new drag & drop API.
The hidden
attribute indicates that an element is not yet, or is no longer, relevant.
WHATWG HTML has the inert
attribute, intended to make dialog
elements modal.
The role
and aria-*
collection attributes which can be used to instruct assistive technology.
The spellcheck
attribute allows for hinting whether content can be checked for spelling or not.
The translate
attribute gives a hint to translators whether the content should be translated.
HTML5 also makes all event handler attributes from HTML4, which take the form onevent
, global attributes and adds several new event handler attributes for new events it defines. For instance, the onplay
event handler attribute for the play
event which is used by the API for the media elements (video
and audio
).
These elements have slightly modified meanings in HTML5 to better reflect how they are used on the Web or to make them more useful:
The address
element is now scoped by the nearest ancestor article
or body
element.
The 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.
The 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 conforming.
The dl
element now represents an association list of name-value groups, and is no longer said to be appropriate for dialogue.
The hr
element now represents a paragraph-level thematic break.
The 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.
For the 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 interface.
The menu
element is redefined to be useful for toolbars and context menus.
The noscript
element is no longer said to be rendered when the user agent doesn't support a scripting language invoked by a script
element earlier in the document.
The s
element now represents contents that are no longer accurate or no longer relevant.
The script
element can now be used for scripts or for custom data blocks.
The small
element now represents side comments such as small print.
The strong
element now represents importance rather than strong emphasis.
The 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 being misspelt.
Several attributes have changed in various ways.
The accept
attribute on input
now allows the values audio/*
, video/*
and image/*
.
The accesskey
global attribute now allows multiple characters to be specified, which the user agent can choose from.
The action
attribute on form
is no longer allowed to have an empty URL.
In WHATWG HTML, the method
attribute has a new keyword dialog
, intended to close a dialog
element.
The border
attribute on table
only allows the values "1" and the empty string. In WHATWG HTML, the border
attribute is obsolete.
The colspan
attribute on td
and th
now has to be greater than zero.
The coords
attribute on area
no longer allows a percentage value of the radius when the element is in the circle state.
The data
attribute on object
is no longer said to be relative to the codebase
attribute.
The defer
attribute on script
now explicitly makes the script execute when the page has finished parsing.
The dir
global attribute now allows the value auto
.
The enctype
attribute on form
now supports the value text/plain
.
The width
and height
attributes on img
, iframe
and 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.
The href
attribute on link
is no longer allowed to have an empty URL.
The href
attribute on base
is now allowed to contain a relative URL.
All attributes that take URLs, e.g. href
on the a
element, now support IRIs if the document's encoding is UTF-8 or UTF-16.
The http-equiv
attribute on meta
is no longer said to be used by HTTP servers to create HTTP headers in the HTTP response. Instead, it is said to be a pragma directive to be used by the user agent.
The id
global 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.
The lang
global attribute takes the empty string in addition to a valid language identifier, just like xml:lang
does in XML.
The media
attribute on link
now accepts a media query and defaults to "all".
The event handler attributes (e.g. onclick
) now always use JavaScript as the scripting language.
The value
attribute of the li
element is no longer deprecated as it is not presentational. The same goes for the start
and type
attributes of the ol
element.
The style
global attribute now always uses CSS as the styling language.
The tabindex
global attribute now allows negative values which indicate that the element can receive focus but cannot be tabbed to.
The target
attribute of the a
and area
elements is no longer deprecated, as it is useful in Web applications, e.g. in conjunction with iframe
.
The type
attribute on script
and style
is no longer required if the scripting language is JavaScript and the styling language is CSS, respectively.
The usemap
attribute on img
no longer takes a URL, but instead takes a valid hash-name reference to a map
element.
The following attributes are allowed but authors are discouraged from using them and instead strongly encouraged to use an alternative solution:
The border
attribute on img
. It is required to have the value "0
" when present. Authors can use CSS instead.
The language
attribute on script
. It is required to have the value "JavaScript
" (case-insensitive) when present and cannot conflict with the type
attribute. Authors can simply omit it as it has no useful function.
The name
attribute on a
. Authors can use the id
attribute instead.
The elements in this section are not to be used by authors. User agents will still have to support them and various sections in HTML5 define how. E.g. the obsolete isindex
element is handled by the parser section.
The following elements are not in HTML5 because their effect is purely presentational and their function is better handled by CSS:
The following elements are not in HTML5 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:
acronym
is not included because it has created a lot of confusion. Authors are to use abbr
for abbreviations.applet
has been obsoleted in favor of object
. isindex
usage can be replaced by usage of form controls. dir
has been obsoleted in favor of ul
. Finally the 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 HTML5. The specification defines how user agents should process them in legacy documents, but authors must not use them and they will not validate.
HTML5 has advice on what you can use instead.
rev
and charset
attributes on link
and a
. shape
and coords
attributes on a
. longdesc
attribute on img
and iframe
. target
attribute on link
. nohref
attribute on area
. profile
attribute on head
. version
attribute on html
. name
attribute on img
(use id
instead). scheme
attribute on meta
. archive
, classid
, codebase
, codetype
, declare
and standby
attributes on object
. valuetype
and type
attributes on param
. axis
and abbr
attributes on td
and th
. scope
attribute on td
. summary
attribute on table
. In addition, HTML5 has none of the presentational attributes that were in HTML4 as their functions are better handled by CSS:
align
attribute on caption
, iframe
, img
, input
, object
, legend
, table
, hr
, div
, h1
, h2
, h3
, h4
, h5
, h6
, p
, col
, colgroup
, tbody
, td
, tfoot
, th
, thead
and tr
. alink
, link
, text
and vlink
attributes on body
. background
attribute on body
. bgcolor
attribute on table
, tr
, td
, th
and body
. border
attribute on object
. cellpadding
and cellspacing
attributes on table
. char
and charoff
attributes on col
, colgroup
, tbody
, td
, tfoot
, th
, thead
and tr
. clear
attribute on br
. compact
attribute on dl
, menu
, ol
and ul
. frame
attribute on table
. frameborder
attribute on iframe
. height
attribute on td
and th
. hspace
and vspace
attributes on img
and object
. marginheight
and marginwidth
attributes on iframe
. noshade
attribute on hr
. nowrap
attribute on td
and th
. rules
attribute on table
. scrolling
attribute on iframe
. size
attribute on hr
. type
attribute on li
, and ul
. valign
attribute on col
, colgroup
, tbody
, td
, tfoot
, th
, thead
and tr
. width
attribute on hr
, table
, td
, th
, col
, colgroup
and pre
. 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" (e.g. span
, img
, text), and "block-level" (e.g. div
, hr
, table
). Some elements did not fit in either category.
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. dl
, table
), or did now allow any children at all (e.g. link
, img
, hr
).
Notice the difference between an element itself being in a certain category, and having a content model of a certain category. For instance, the 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.
HTML5 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.
link
, script
. span
, div
, text. This is roughly like HTML4's "block-level" and "inline" together. aside
, section
. h1
, hgroup
. span
, img
, text. This is roughly like HTML4's "inline". Elements that are phrasing content are also flow content. img
, iframe
, svg
. a
, button
, label
. Interactive content is not allowed to be nested. As broad changes from HTML4, HTML5 no longer has any element that only accepts what HTML4 called "block-level" elements; e.g. the body
element now allows flow content. This is thus closer to HTML4 Transitional than HTML4 Strict.
Further changes include:
The address
element now allows flow content, but with no heading content descendants, no sectioning content descendants, and no header
, footer
, or address
element descendants.
WHATWG HTML allows link
and meta
as descendants of body
if they use microdata attributes.
The noscript
element was a "block-level" element in HTML4, but is phrasing content in HTML5.
The table
, thead
, tbody
, tfoot
, tr
, ol
, ul
and dl
elements are allowed to be empty in HTML5.
Table elements have to conform to the table model (e.g. two cells are not allowed to overlap).
The table
element now does not allow col
elements as direct children. However, the HTML parser implies a colgroup
element, so this change should not affect text/html
content.
The table
element now allows the tfoot
element to be the last child.
The caption
element now allows flow content, but with no descendant table
elements.
The th
element now allows flow content, but with no header
, footer
, sectioning content, or heading content descendants.
The 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 content.
The ins
and del
elements also have a transparent content model. HTML4 had similar rules in prose that could not be expressed in the DTD.
The object
element also has a transparent content model, after its param
children.
The map
element also has a transparent content model. The area
element is considered phrasing content if there is a map
element ancestor, which means that they do not need to be direct children of map
.
HTML5 has introduced many new APIs and have extended, changed or obsoleted some existing APIs.
HTML5 introduces a number of APIs that help in creating Web applications. These can be used together with the new elements introduced for applications:
Media elements (video
and audio
) have APIs for controlling playback, syncronising multiple media elements, and timed text tracks (e.g. subtitles).
An API for form constraint validation (e.g. the setCustomValidity()
method).
An API for commands that the user can invoke (used together with the command
element among others).
An API that enables offline Web applications, with an application cache.
An API that allows a Web application to register itself for certain protocols or media types, using registerProtocolHandler()
and registerContentHandler()
.
Editing API in combination with a new global contenteditable
attribute.
Drag & drop API in combination with a draggable
attribute.
An API that exposes the components of the document's URL and allows scripts to navigate, redirect and reload (the Location
interface).
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" navigation (the History
interface).
An API to schedule timer-based callbacks (setTimeout()
and setInterval()
).
An API to prompt the user (alert()
, confirm()
, prompt()
, showModalDialog()
).
An API for printing the document (print()
).
An API for handling search providers (AddSearchProvider()
and IsSearchProviderInstalled()
).
The Window
object has been defined.
WHATWG HTML has further APIs that are not in HTML5 but are separate specifications at the W3C:
An API for microdata.
An API for immediate-mode bitmap graphics (the 2d
context for the canvas
element).
An API for cross-document messaging and channel messaging (postMessage()
and MessageChannel
).
An API for runnings scripts in the background (Worker
and SharedWorker
).
An API for client-side storage (localStorage
and sessionStorage
).
An API for bidirectional client-server communication (WebSocket
).
An API for server-to-client data push (EventSource
).
The following features from DOM Level 2 HTML are changed in various ways:
document.title
now collapses whitespace on getting.
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.close()
, document.write()
and 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, or can imply a call to document.open()
or be ignored altogether in some cases.
document.getElementsByName()
now returns all HTML elements with a name
attribute matching the argument.
elements
on HTMLFormElement
now returns an HTMLFormControlsCollection
of button
, fieldset
, input
, keygen
, object
, output
, select
and textarea
elements. length
returns the number of nodes in elements
.
add()
on HTMLSelectElement
now also accepts an integer as its second argument.
remove()
on HTMLSelectElement
now removes the first element in the collection if the argument is out of bounds.
The click()
, focus()
and blur()
methods are now available on all HTML elements.
Document
DOM Level 2 HTML had an HTMLDocument
interface that inherited from Document
and provided HTML-specific members on documents. HTML5 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:
location
, lastModified
and readyState
to help resource metadata management.
dir
, head
, embeds
, plugins
, scripts
, commands
, and a generic name getter, to access various parts of the DOM tree. WHATWG HTML also has getItems()
for microdata and cssElementMap
to accompany the CSS element()
feature.
activeElement
and hasFocus
to determine which element is currently focused and whether the Document
has focus respectively.
designMode
, execCommand()
, queryCommandEnabled()
, queryCommandIndeterm()
, queryCommandState()
, queryCommandSupported()
, queryCommandValue()
for the editing API.
All event handler IDL attributes. Also, onreadystatechange
is a special event handler IDL attribute that is only available on Document
.
Existing scripts that modified the prototype of HTMLDocument
should continue to work because window.HTMLDocument
now returns the Document
interface object.
HTMLElement
The HTMLElement
interface has also gained several extensions in HTML5:
translate
, hidden
, tabIndex
, accessKey
, draggable
, dropzone
, contentEditable
, contextMenu
, spellcheck
and style
reflect content attributes.
classList
is a convenient accessor for className
. The object it returns, exposes methods (contains()
, add()
, remove()
, and toggle()
) for manipulating the element's classes.
dataset
is a convenience feature for handling the data-*
attributes, which are exposed as camel-cased properties. For instance, elm.dataset.fooBar = 'test'
sets the data-foo-bar
content attribute on elm
.
WHATWG HTML has itemScope
, itemType
, itemId
, itemRef
, itemProp
, properties
and itemValue
for microdata.
click()
, focus()
and blur()
allows scripts to simulate clicks and moving focus.
accessKeyLabel
gives the shortcut key that the user agent has assigned for the element, which the author can influence with the accesskey
attribute.
isContentEditable
returns true if the element is editable.
commandType
, commandLabel
, commandIcon
, commandHidden
, commandDisabled
and commandChecked
is part of the command API.
All event handler IDL attributes.
Some interfaces in DOM Level 2 HTML have been extended.
HTMLOptionsCollection
now has a legacy caller, setter creator, and the members add()
, remove()
and selectedIndex
HTMLLinkElement
and HTMLStyleElement
now implement the LinkStyle
interface from CSSOM. [CSSOM]
HTMLFormElement
now has a named getter and an indexed getter.
HTMLSelectElement
now has a getter, item()
and namedItem()
methods, a setter creator, selectedOptions
and labels
IDL attributes, and members for the form constrain validation API: willValidate
, validity
, validationMessage
, checkValidity()
and setCustomValidity()
.
HTMLOptionElement
now has a constructor Option
.
HTMLInputElement
now has the members files
, height
, indeterminate
, list
, valueAsDate
, valueAsNumber
, width
, stepUp()
, stepDown()
, the form constraint validation API members, labels
, members for the text field selection API: selectionStart
, selectionEnd
, selectionDirection
, setSelectionRange()
and setRangeText()
.
HTMLTextAreaElement
now has the members textLength
, the form constraint validation API members, labels
and the text field selection API members.
HTMLButtonElement
now has the form constraint validation API members and labels
.
HTMLLabelElement
now has the member control
.
HTMLFieldSetElement
now has the members type
, elements
and the form constraint validation API members.
HTMLAnchorElement
now has the members relList
, text
, the URL decomposition IDL attributes: protocol
, host
, hostname
, port
, pathname
, search
and hash
. HTMLLinkElement
and HTMLAreaElement
also have the relList
IDL attribute. HTMLAreaElement
also has the URL decomposition IDL attributes.
HTMLImageElement
now has a constructor Image
, the members naturalWidth
, naturalHeight
and complete
.
HTMLObjectElement
now has the members contentWindow
, the form constraint validation API members and a legacy caller.
HTMLMapElement
now has the member images
.
HTMLTableElement
now has the member createTBody()
.
HTMLIFrameElement
now has the member contentWindow
.
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 obsolete bgcolor
content attribute.
The following interfaces are marked obsolete since the elements are obsolete: HTMLAppletElement
, HTMLFrameSetElement
, HTMLFrameElement
, HTMLBaseFontElement
, HTMLDirectoryElement
and HTMLFontElement
.
The HTMLIsIndexElement
interface is removed altogether since the HTML parser expands an isindex
tag into other elements.
The following members of the HTMLDocument
interface (which have now moved to Document
) are now obsolete: anchors
and applets
.
The changelogs in this section indicate what has been changed between publications of the HTML5 drafts, as well as changes in WHATWG HTML that do not affect HTML5. Rationale for changes can be found in the public-html@w3.org and whatwg@whatwg. org 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 chronological order.
ruby
was changed with regards to nested ruby
elements. script
tags in the HTML syntax now execute. find()
API has been dropped. inBandMetadataTrackDispatchType
IDL attribute was added to TextTrack
. 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 startDate
. Further changes to WHATWG HTML that do not affect HTML5:
addElement()
was dropped from the Drag and Drop API. iframe
elements with the seamless
attribute. :enabled
and :disabled
pseudo-classes now apply to input
elements in the Hidden state. ssh
, sip
and magnet
schemes are now in the registerProtocolHandler()
whitelist. table
elements now have 'box-sizing:border-box' by default. hidden
attribute. alt
text can now use a specific attribute on img
that makes validators ignore the missing alt
error. data:
URLs. inputmode
attribute has been added to input
and textarea
. autocomplete
attribute has been extended to support prefilling specific things. ArrayBufferView
as well as ArrayBuffer
. border
attribute on table
is non-conforming again. connect
event now also exposes the source port in the source
IDL attribute. send()
. setRangeText()
method has been added to input
and textarea
. srcset
attribute has been added to img
. prefer-online
mode. dialog
element, the inert
global attribute and the dialog
method on form
. resetTransform()
method, currentTransform
IDL attribute, several IDL attributes for font metrics, resetClip()
method, imageSmoothingEnabled
IDL attribute, addHitRegion()
method, removeHitRegion()
method, support for dashed lines, have been added to the canvas 2d context. TextTrackCue
members alignment
, linePosition
, textPosition
and direction
were renamed to align
, line
, position
and vertical
, respectively. command
element now has a command
attribute. translate
global attribute was added. showModalDialog()
, alert()
, confirm()
and prompt()
methods are now allowed to do nothing during pagehide
, beforeunload
and unload
events. script
element now supports beforescriptexecute
and afterscriptexecute
events. window.onerror
now supports a fourth argument for column position. window.opener
IDL attribute can now return null in some cases. clearTimeout()
and clearInterval()
methods were made synonymous. @global
at-rule was introduced, for use together with style
elements with the scoped
attribute. embed
and object
elements now have a legacy caller. window.onerror
's return value was changed to match reality. setTimeout()
API is now allowed to be throttled in background tabs. :valid
and :invalid
pseudo-classes now apply to form
elements. 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 "f:
". cueAsSource
IDL attribute on TextTrackCue
got renamed to text
. window.onerror
API is now invoked with dummy arguments for cross-origin scripts. textarea
element's value
and 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. 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 XMLDocument
interface. HTMLDocument
moved to Document
and window.HTMLDocument
now just returns window.Document
. MutableTextTrack
and TextTrack
interfaces were merged and TextTrackCue
was made more mutable. selectedOption
IDL attribute on input
was dropped. readyState
IDL attribute moved from TextTrack
to HTMLTrackElement
. text/html-sandboxed
MIME type was dropped. .
" character. header
, footer
, sectioning content or heading content descendants. addtrack
event on the relevant track list objects. currentTime
on media elements before the media has loaded now defers the seek instead of throwing. iframe
s if they honor the sandbox
attribute. MediaController
s now get paused when they end. init*Event()
methods were removed. suspend
event when the resource is loaded. br
element. UndoManager
and related features moved to UndoManager and DOM Transaction. isProtocolHandlerRegistered()
, isContentHandlerRegistered()
, unregisterProtocolHandler()
and 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 "web+
". text/html
resources now don't need to point to an element with a matching ID. audio
elements are now allowed to have zero source
children. maxlength
and size
attributes are allowed (but give warnings in validators) on input
elements with type=number
. shortcut icon
" is now allowed. heading
and tab
roles. 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. abort()
method. HTMLCollection
, DOMTokenList
, getElementsByClassName()
, createHTMLDocument()
, HTML-specific overrides to some DOM Core features (like createElement()
), some definitions, the id
IDL attribute and ID handling moved to DOM4. pushState()
and replaceState()
methods now change the history entry to GET. commandLabel
, commandIcon
, commandHidden
, commandDisabled
and commandChecked
. window.postMessage
now supports transferring some objects instead of cloning them, and supports transferring ArrayBuffer
. placeholder
attribute is now allowed on input
elements with type=number
. MediaController
gained an onended
event listener. object
element gained a new attribute typemustmatch
, to make it safer for authors to embed untrusted resources where they expect a certain content type. form
attribute was removed from meter
and progress
. ruby
. text/plain
) that are guaranteed to never be supported as scripting types for script
were specified, so authors can safely use them for custom data blocks. about:blank
documents created from window.open()
now get a load
event. window.status
was specified to exist but do nothing. DataTransferItems
was renamed to DataTransferItemList
. crossorigin
attribute has been added to img
, video
and audio
to use CORS. external
IDL attribute has been added on window
and has the members AddSearchProvider()
and IsSearchProviderInstalled()
. Further changes to WHATWG HTML that do not affect HTML5:
arc()
and arcTo()
methods and the new ellipse()
method. Path
objects. SVG path data can be added to a Path
. http+aes:
and 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 href
on a
elements), that attribute is now required. PeerConnection
was moved to WebRTC. CLOSING
state. itemtype
attribute now allows multiple types. CanvasPixelArray
was dropped in favor of Uint8ClampedArray
. link
element is no longer allowed to have both rel
and itemprop
. a
element got a new download
attribute. This attribute is not included in HTML5. window.find()
method was added. fillText()
and strokeText()
methods now do not collapse whitespace. location
now stringifies. onerror
handler. EventSource
now supports CORS. EventSource
was made stricter in its MIME type checking. atob()
and btoa()
methods. ononline
and onoffline
event handlers. error
event again. PeerConnection
API. javascript:
scheme in img
, object
, CSS, etc, has been dropped. toBlob()
method has been added to canvas
. drawFocusRing()
method on the canvas
2d context has been split into two methods, drawSystemFocusRing()
and drawCustomFocusRing()
. values
attribute on PropertyNodeList
has been replaced with a getValues()
method. select
event has been specified. selectDirection
IDL attribute has been added to input
and textarea
. :enabled
and :disabled
pseudo-classes now match fieldset
, and the :indeterminate
pseudo-class can now match progress
. getKind()
method has been added to TrackList
. MediaController
API and the mediagroup
attribute have been added to synchronize playback of media elements. getName()
method on TrackList
was renamed to getLabel()
. 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 muted
attribute. Content-Language
meta pragma is now non-conforming. pushState
and replaceState
features have been changed based on implementation feedback in Firefox, and history.state
has been introduced. tracks
IDL attribute on media elements has been renamed to textTracks
. forminput
and formchange
events, and the dispatchFormInput()
and dispatchFormChange()
methods have been dropped. rel
keywords archives
, up
, last
, index
, first
and related synonyms have been dropped. video
element's letterboxing rules are now specified in terms of CSS 'object-fit'. canvas
. onerror
event handler on window
is now invoked for compile-time script errors as well as runtime errors. script
elements now have async
default to true
, which can be set to false
to make the scripts execute in insertion order. atob()
and btoa()
methods have been specified. .manifest
to .appcache
. action
and formaction
attributes are no longer allowed to have the empty string as value. dropzone
attribute was added.bdi
element was added to aid with user-generated content that may have bidi implications.dir
attribute gained a new "auto
" value.dirname
attribute was added to input
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. The getSelection()
API moved to a separate DOM Range draft. Similarly UndoManager
has been removed from the W3C copy of HTML5 for now as it is not ready yet.
hidden
attribute now works for table-related elements.canvas
getContext()
method is now defined to be able to handle multiple contexts better.startTime
IDL attribute was renamed to initialTime
and startOffsetTime
was added.prefetch
link relationship can now be used on a
elements.datetime
attribute of ins
and del
no longer requires a time to be specified.form
element is no longer supported.s
element is no longer deprecated.video
element has a new audio
attribute.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 iframe
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 meta
element.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 rel
attribute of the link
element can now be used to point to feeds again, even if the feed is not an alternative for the document.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 it.document.head
has been introduced to provide convenient access to the head
element from script.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.meter
and progress
elements no longer have "magic" processing of their contents because it could not be made to work internationally.meter
and progress
elements, as well as the output
element, can now be labeled using the label
element.text/html-sandboxed
, was introduced to allow hosting of potentially hostile content without it causing harm.srcdoc
attribute for the iframe
element was introduced to allow embedding of potentially hostile content inline. It is expected to be used together with the sandbox
and seamless
attributes.figure
element now uses a new element figcaption
rather than legend
because people want to use HTML5 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 to preload
.A whole lot of other smaller issues have also been resolved. The above list summarizes what is thought to be of primary interest to authors.
In addition to all of the above, Microdata, the 2D context API for canvas
, and Web Messaging (postMessage()
API) have been split into their own drafts at the W3C (the WHATWG still publishes a version of HTML5 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 HTML5 still includes them.
time
element is empty user agents have to render the time in a locale-specific manner.load
event is dispatched at Window
, but now has Document
as its target.pushState()
now affects the Referer
(sic) header.onundo
and onredo
are now on Window
.startTime
member that indicates where the current resource starts.header
has been renamed to hgroup
and a new header
element has been introduced.createImageData()
now also takes ImageData
objects.createPattern()
can now take a video
element as argument too.footer
element is no longer allowed in header
and header
is not allowed in address
or footer
.<input type="tel">
accesskey
is now properly defined.section
and article
now take a cite
attribute.textLength
has been added as member of the textarea
element.rp
element now takes phrasing content rather than a single character.location.reload()
is now defined.hashchange
event now fires asynchronously.spellcheck
IDL attribute now maps to a DOMString
.hasFeature()
support has been reduced to a minimum.Audio()
constructor sets the autobuffer
attribute.td
element is no longer allowed in thead
.input
element and DataTransfer
object now have a files
IDL attribute.datagrid
and bb
have been removed due to their design not being agreed upon.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 HTML5 have been taken out and will likely be further developed at the IETF:
spellcheck
has been added.this
in the global object returns a WindowProxy
object rather than the Window
object.value
IDL attribute for input
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 take a video
element as well.document.domain
is now IPv6-compatible.video
element gained an autobuffer
boolean attribute that serves as a hint.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.)bufferingRate
and bufferingThrottled
members of media elements have been removed.postMessage()
API now takes an array of MessagePort
objects rather than just one.add()
method on the select
element and the options
member of the select
element is now optional.action
, enctype
, method
, novalidate
, and target
attributes on input
and button
elements have been renamed to formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
.document.cookie
and localStorage
) at the same time. The Navigator
gained a getStorageUpdates()
method to allow it to be explicitly released.text/html
resources.placeholder
attribute has been added to the textarea
element.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 HTML5 have been taken out and will be further developed by the Web Applications Working Group as standalone specifications:
localStorage
and sessionStorage
)data
member of ImageData
objects has been changed from an array to a CanvasPixelArray
object.canvas
element and its API.canvas
is clarified.canvas
have been made in response to implementation and author feedback. E.g. clarifying what happens when NaN and Infinity are passed and fixing the definitions of arc()
and arcTo()
.innerHTML
in XML was slightly changed to improve round-tripping.toDataURL()
method on the canvas
element now supports setting a quality level when the media type argument is image/jpeg
.poster
attribute of the video
element now affects its intrinsic dimensions.type
attribute of the link
element has been clarified.link
when the expected type is an image.href
attribute of the base
element does not depend on xml:base
.xmlns
attribute with the value http://www.w3.org/1999/xhtml
is now allowed on all HTML elements.data-*
attributes and custom attributes on the embed
element now have to match the XML Name
production and cannot contain a colon.volume
on media elements is now 1.0 rather than 0.5.event-source
was renamed to eventsource
because no other HTML element uses a hyphen.postMessage()
.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.parent
attribute of the Window
object 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 work.)embed
can now be used without its src
attribute.getElementsByClassName()
is defined to be ASCII case-insensitive in quirks mode for consistency with CSS.localName
no longer returns the node name in uppercase.data-*
attributes are defined to be always lowercase.opener
attribute of the Window
object is not to be present when the page was opened from a link with target="_blank"
and rel="noreferrer"
.top
attribute of the Window
object is now defined.a
element now allows nested flow content, but not nested interactive content.header
element means to document summaries and table of contents.canvas
element.autosubmit
attribute has been removed from the menu
element.outerHTML
and insertAdjacentHTML()
has been added.xml:lang
is now allowed in HTML when lang
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 Window
object is now defined.alt
attribute is omitted a title
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 hidden
.definitionURL
attribute of MathML is now properly supported. Previously it would have ended up being all lowercase during parsing.datatemplate
, rule
and nest
elements).loop
attribute.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 source
element.canPlayType()
has been added to the media elements.totalBytes
and bufferedBytes
attributes have been removed from the media elements.Location
object gained a resolveURL()
method.q
element has changed again. Punctuation is to be provided by the user agent again.unload
and beforeunload
events are now defined.headers
attribute pointing to a td
or th
element, but authors are required to only let them point to th
elements.http-equiv
values.meta
element has a charset
attribute it must occur within the first 512 bytes.StorageEvent
object now has a storageArea
attribute.foreignObject
element.HTMLDocument
and Window
objects is now defined.Window
object gained the locationbar
, menubar
, personalbar
, scrollbars
, statusbar
and toolbar
attributes giving information about the user interface.document.domain
now relies on the Public Suffix List. [PSL]Web Forms 2.0, previously a standalone specification, has been fully integrated into HTML5 since last publication. The following changes were made to the forms chapter:
select
and datalist
elements through the data
attribute has been removed.form
attribute.dispatchChangeInput()
and dispatchFormChange()
methods have been removed from the select
, input
, textarea
, and button
elements.inputmode
attribute has been removed.input
element in the File Upload state no longer supports the min
and max
attributes.allow
attribute on input
elements in the File Upload state is no longer authoritative.pattern
and accept
attributes for textarea
have been removed.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 input
element is now conforming (rather than deprecated).object
elements now partake in form submission.type
attribute of the input
element gained the values color
and search
.input
element gained a multiple
attribute which allows for either multiple e-mails or multiple files to be uploaded depending on the value of the type
attribute.input
, button
and form
elements now have a novalidate
attribute to indicate that the form fields should not be required to have valid values upon submission.label
element contains an input
it may still have a for
attribute as long as it points to the input
element it contains.input
element now has an indeterminate
IDL attribute.input
element gained a placeholder
attribute.ping
attribute have changed. <meta http-equiv=content-type>
is now a conforming way to set the character encoding.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. dataTransfer
object now has a types
attribute indicating the type of data being transferred. m
element is now called mark
. figure
element no longer requires a caption. ol
element has a new reversed
attribute. queryCommandEnabled()
and related methods. headers
attribute has been added for td
elements. table
element has a new createTBody()
method. data-name
and can access these through the DOM using 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 _blank
. 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 encoding error. bufferedBytes
, totalBytes
and bufferingThrottled
IDL attributes have been added to the video
element. begin
event has been renamed to loadstart
for consistency with the Progress Events specification. charset
attribute has been added to script
. iframe
element has gained the sandbox
and seamless
attributes which provide sandboxing functionality. ruby
, rt
and rp
elements have been added to support ruby annotation. showNotification()
method has been added to show notification messages to the user. beforeprint
and afterprint
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, 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, Toby Inkster, 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!