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Introduction to XHTML

Original Author(s): Markus Gylling

W3Cs view

The XHTML family is designed to accommodate extensions through XHTML modules. These modules will permit the combination of existing and new feature sets when developing content and when designing new user agents.

Alternate ways of accessing the Internet are constantly being introduced. The XHTML family is designed with general user agent interoperability in mind.

Through a new user agent and document profiling mechanism, servers, proxies, and user agents will be able to perform best effort content transformation. Ultimately, it will be possible to develop XHTML-conforming content that is usable by any XHTML-conforming user agent.

Published January 2000, revised 1 August 2002

W3C's first Recommendation for XHTML, following on from earlier work on HTML 4.01, HTML 4.0, HTML 3.2 and HTML 2.0.

Is a reformulation of HTML 4.01 in XML, and combines the strength of HTML 4 with the power of XML.

Relies on HTML 4.01 for the meanings of XHTML elements and attributes.

  • cell phones,
  • televisions,
  • cars,
  • wallet sized wireless communicators,
  • kiosks
  • desktops

Can be interpreted by existing browsers by following a few simple guidelines

HTML documents can be converted into XHTML using the Open Source HTML Tidy utility.

Three flavors -- three DTDs.

XHTML 1.0 Strict
For really clean structural mark-up, free of any markup associated with layout.
XHTML 1.0 Transitional
take advantage of XHTML features including style sheets but nonetheless to make small adjustments to your markup for the benefit of those viewing your pages with older browsers which can't understand style sheets. These include using the body element with bgcolor, text and link attributes.
XHTML 1.0 Frameset
When using Frames to partition the browser window into two or more frames.

Published December 2000

  • Includes the minimal set of modules required to be an XHTML Host Language document type
  • In addition it includes images, forms, basic tables, and object
  • Is designed for Web clients that do not support the full set of XHTML features;
    • Web clients such as mobile phones
    • PDAs
    • pagers
    • settop boxes
  • Is rich enough for content authoring.

Is designed as an extensible common base.

Is implemented using XHTML modules.

Published April 2001

  • An abstract modularization of XHTML
  • provides a means for subsetting and extending XHTML
  • a feature needed for extending XHTML's reach onto emerging platforms.
Modularization of XHTML will make it easier to combine with markup tags for things like vector graphics, multimedia, math, electronic commerce and more. Content providers will find it easier to produce content for a wide range of platforms, with better assurances as to how the content is rendered.
The modular design reflects the realization that a one-size-fits-all approach will no longer work in a world where browsers vary enormously in their capabilities. A browser in a cellphone can't offer the same experience as a top of the range multimedia desktop machine. The cellphone doesn't even have the memory to load the page designed for the desktop browser.
  • Defines a new XHTML document type
  • based upon the module framework and modules defined in Modularization of XHTML
  • serve as the basis for future extended XHTML 'family' document types
  • removes the deprecated legacy functionality of HTML 4 that was brought forward into the XHTML 1.0 document types.
  • Introduces a Ruby module.
What is the difference between XHTML 1.0, XHTML Basic and XHTML 1.1?

The first step was to reformulate HTML 4 in XML, resulting in XHTML 1.0. By following the HTML Compatibility Guidelines set forth in Appendix C of the XHTML 1.0 specification, XHTML 1.0 documents could be compatible with existing HTML user agents.

The next step is to modularize the elements and attributes into convenient collections for use in documents that combine XHTML with other tag sets. The modules are defined in Modularization of XHTML. XHTML Basic is an example of fairly minimal build of these modules and is targeted at mobile applications.

XHTML 1.1 is an example of a larger build of the modules, avoiding many of the presentation features. While XHTML 1.1 looks very similar to XHTML 1.0 Strict, it is designed to serve as the basis for future extended XHTML Family document types, and its modular design makes it easier to add other modules as needed or integrate itself into other markup languages. XHTML 1.1 plus MathML 2.0 document type is an example of such XHTML Family document type.

Current Status: Working Draft May 2003

The aims of XHTML2 include:

  • As generic XML as possible
  • Less presentation, more structure
  • More usability
  • More accessibility
  • Better internationalization
  • More device independence (single authoring)
  • Less scripting

How has XHTML been recieved by webmasters worldwide since its introduction?

Which of the different XHTML versions is the safest/smartest to use today?

XHTML 1 SE Recommendation XHTML Basic Recommendation Modularization of XHTML Recommendation XHTML 2 Working Draft

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This page was last edited by PVerma on Friday, August 6, 2010 23:22
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