W3C

HTML 5

A vocabulary and associated APIs for HTML and XHTML

W3C Working Draft 25 August 2009

This Version:
http://www.w3.org/TR/2009/WD-html5-20090825/
Latest Published Version:
http://www.w3.org/TR/html5/
Latest Editor's Draft:
http://www.w3.org/html/wg/html5/
Previous Versions:
http://www.w3.org/TR/2009/WD-html5-20090423/
http://www.w3.org/TR/2009/WD-html5-20090212/
http://www.w3.org/TR/2008/WD-html5-20080610/
http://www.w3.org/TR/2008/WD-html5-20080122/
Editors:
Ian Hickson, Google, Inc.
David Hyatt, Apple, Inc.

This specification is available in the following formats: single page HTML, multipage HTML. This is revision 1.2852.


Abstract

This specification defines the 5th major revision of the core language of the World Wide Web: the Hypertext Markup Language (HTML). In this version, new features are introduced to help Web application authors, new elements are introduced based on research into prevailing authoring practices, and special attention has been given to defining clear conformance criteria for user agents in an effort to improve interoperability.

Status of this document

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 most recently formally published revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

The WHATWG version of this specification is available under a license that permits reuse of the specification text.

If you wish to make comments regarding this document, please send them to public-html-comments@w3.org (subscribe, archives) or whatwg@whatwg.org (subscribe, archives), or submit them using our public bug database. All feedback is welcome.

We maintain a list of all e-mails that have not yet been considered and a list of all bug reports that have not yet been resolved.

Implementors should be aware that this specification is not stable. Implementors who are not taking part in the discussions are likely to find the specification changing out from under them in incompatible ways. Vendors interested in implementing this specification before it eventually reaches the Candidate Recommendation stage should join the aforementioned mailing lists and take part in the discussions.

The publication of this document by the W3C as a W3C Working Draft does not imply that all of the participants in the W3C HTML working group endorse the contents of the specification. Indeed, for any section of the specification, one can usually find many members of the working group or of the W3C as a whole who object strongly to the current text, the existence of the section at all, or the idea that the working group should even spend time discussing the concept of that section.

The latest stable version of the editor's draft of this specification is always available on the W3C CVS server and in the WHATWG Subversion repository. The latest editor's working copy (which may contain unfinished text in the process of being prepared) is also available.

There are various ways to follow the change history for the specification:

E-mail notifications of changes
HTML-Diffs mailing list (diff-marked HTML versions for each change): http://lists.w3.org/Archives/Public/public-html-diffs/latest
Commit-Watchers mailing list (complete source diffs): http://lists.whatwg.org/listinfo.cgi/commit-watchers-whatwg.org
Real-time notifications of changes:
Generated diff-marked HTML versions for each change: http://twitter.com/HTML5
All (non-editorial) changes to the spec source: http://twitter.com/WHATWG
Browsable version-control record of all changes:
CVSWeb interface with side-by-side diffs: http://dev.w3.org/cvsweb/html5/spec/Overview.html
Annotated summary with unified diffs: http://html5.org/tools/web-apps-tracker
Raw Subversion interface: svn checkout http://svn.whatwg.org/webapps/

The W3C HTML Working Group is the W3C working group responsible for this specification's progress along the W3C Recommendation track. This specification is the 25 August 2009 Working Draft.

This specification is also being produced by the WHATWG. The two specifications are identical from the table of contents onwards.

This specification is intended to replace (be a new version of) what was previously the HTML4, XHTML 1.0, and DOM2 HTML specifications.

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.

Stability

Different parts of this specification are at different levels of maturity.

Table of contents

  1. 1 Introduction
    1. 1.1 Background
    2. 1.2 Audience
    3. 1.3 Scope
    4. 1.4 History
    5. 1.5 Design notes
      1. 1.5.1 Serializability of script execution
      2. 1.5.2 Compliance with other specifications
    6. 1.6 Relationships to other specifications
      1. 1.6.1 Relationship to HTML 4.01 and DOM2 HTML
      2. 1.6.2 Relationship to XHTML 1.x
    7. 1.7 HTML vs XHTML
    8. 1.8 Structure of this specification
      1. 1.8.1 How to read this specification
      2. 1.8.2 Typographic conventions
    9. 1.9 A quick introduction to HTML
  2. 2 Common infrastructure
    1. 2.1 Terminology
      1. 2.1.1 Resources
      2. 2.1.2 XML
      3. 2.1.3 DOM trees
      4. 2.1.4 Scripting
      5. 2.1.5 Plugins
      6. 2.1.6 Character encodings
    2. 2.2 Conformance requirements
      1. 2.2.1 Dependencies
      2. 2.2.2 Extensibility
    3. 2.3 Case-sensitivity and string comparison
    4. 2.4 Common microsyntaxes
      1. 2.4.1 Common parser idioms
      2. 2.4.2 Boolean attributes
      3. 2.4.3 Keywords and enumerated attributes
      4. 2.4.4 Numbers
        1. 2.4.4.1 Non-negative integers
        2. 2.4.4.2 Signed integers
        3. 2.4.4.3 Real numbers
        4. 2.4.4.4 Ratios
        5. 2.4.4.5 Percentages and lengths
        6. 2.4.4.6 Lists of integers
        7. 2.4.4.7 Lists of dimensions
      5. 2.4.5 Dates and times
        1. 2.4.5.1 Months
        2. 2.4.5.2 Dates
        3. 2.4.5.3 Times
        4. 2.4.5.4 Local dates and times
        5. 2.4.5.5 Global dates and times
        6. 2.4.5.6 Weeks
        7. 2.4.5.7 Vaguer moments in time
      6. 2.4.6 Colors
      7. 2.4.7 Space-separated tokens
      8. 2.4.8 Comma-separated tokens
      9. 2.4.9 Reversed DNS identifiers
      10. 2.4.10 References
    5. 2.5 URLs
      1. 2.5.1 Terminology
      2. 2.5.2 Dynamic changes to base URLs
      3. 2.5.3 Interfaces for URL manipulation
    6. 2.6 Fetching resources
      1. 2.6.1 Protocol concepts
      2. 2.6.2 Encrypted HTTP and related security concerns
      3. 2.6.3 Determining the type of a resource
    7. 2.7 Character encodings
    8. 2.8 Common DOM interfaces
      1. 2.8.1 Reflecting content attributes in DOM attributes
      2. 2.8.2 Collections
        1. 2.8.2.1 HTMLCollection
        2. 2.8.2.2 HTMLAllCollection
        3. 2.8.2.3 HTMLFormControlsCollection
        4. 2.8.2.4 HTMLOptionsCollection
        5. 2.8.2.5 HTMLPropertyCollection
      3. 2.8.3 DOMTokenList
      4. 2.8.4 DOMSettableTokenList
      5. 2.8.5 Safe passing of structured data
      6. 2.8.6 DOMStringMap
      7. 2.8.7 DOM feature strings
      8. 2.8.8 Exceptions
      9. 2.8.9 Garbage collection