Filename extension .xhtml, .html +, .htm +, .xht, .xml +
Internet media type application/xhtml+xml
Developed by World Wide Web Consortium +
Type Markup language
Standard XHTML 1.0
XHTML 2.0 (Working Draft)
File formats category - v  e   edit
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The Extensible Hypertext Markup Language (XHTML) is a markup language developed by the W3C as an extension of HTML (HTML 4) that conforms to XML syntax.

Document typesEdit

In XHTML 1.0, there are three DTDs which represent corresponding DTDs in HTML 4. These are:

  • XHTML-1.0-Strict - This excludes elements that were deprecated in HTML 4.
  • XHTML-1.0-Transitional - This matches HTML 4 Transitional and includes deprecated elements for backward compatibility.
  • XHTML-1.0-Frameset - Includes deprecated elements as well as support for framesets.


  • XHTML 1.0 is the first version. The second edition became a recommendation in August 2002.
  • XHTML 1.1 follows from XHTML 1.0 Strict, with a few changes: the addition of elements for ruby annotation, and the deprecation of the lang and name attributes.
  • XHTML 2.0
  • HTML 5


XHTML 2.0Edit

XHTML 2.0 added some elements to the XHTML 1.x specification. These include:

  • <section> and <h>

In previous versions, document structure can only be inferred by the location of sections of text (that is, by using <h1>, <h2>, …). The <section> and <h> elements allows to specify the structure explicitly.

  • <hr> is renamed to <separator>.
  • <br /> is replaced by the <l> element, which does not represent line breaks themselves but individual lines.
  • <nl> (navigation list) has been added.
  • The src attribute may be applied to any element, this replaces functionality given by the <img> element. It also allows for fallback functionality given by <object>.
  • The href attribute may be applied to any element and thus may become a hyperlink.
  • The edit attribute may be applied to any element and replaces functionality given by <ins> and <del>.
  • The events structure has been replaced by XML Events.
  • HTML Forms has been replaced by XForms.
  • Frame functionality is redefined through XFrames.
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