Stands for eXtended HyperText Markup Language. Fusion of Xml and Html languages, Xhtml seems to bring the best of both worlds in a powerful multimedia markup language. Requiring a strict grammar inherited from Xml (mandatory closing tags, lowercase attributes, ...etc.) and proposing aninnovative system of Xml modules in addition to Html features, Xhtml offers to developers a new bunch of possibilities and creative skills.

Xhtml 1 : A half success

Initially designed to replace the aging Html 4, Xhtml 1 had to lay foundations for a new family of markup langages, combining multimedia advantages of Html with the rigour and the scalability which characterize Xml. As well as cleverly built, Xhtml 1 was not massively adopted by web developpers.

A first explanation is the incomplete support of Xhtml 1 by the dominating browser in in terms of market share, Microsoft Internet Explorer. Indeed, Microsoft Internet Explorer is only dealing with with a mimetype text/html instead of the official application/xhtml+xml, and does not support natively the inclusions of various Xml sources (MathMl, Svg, ...etc.). One of its competitors, Mozilla Firefox, is only able to offer a small implementation of Svg (Tiny Svg) and exclude by this fact all animation skills proposed by Smil. Opera is currently the only browser offering a full support for Xhtml 1.1. A second accusation that could be done to Xhtml 1 is to not be gone farther in the evolution of Html, especially in two pillars of the web, the web forms (virtually unchanged since Html 2, 1996) and the multimedia part, where needs are growing.

Xhtml 2 : A working draft

Firstly announced as the natural heir of Xhtml 1, Xhtml 2 has been bogged down in a document rather than multimedia orientation, in a domain that did not match with users wishes. Massively rejected by browsers, and despite some good ideas, Xhtml 2 will remain in the draft stage to be replaced by Xhtml 5.

Xhtml 5 : The return to Xhtml roots

As the attentive reader will have noticed, there was not from the W3c any recommendation produced concerning Xhtml 3 or Xhtml 4. Indeed, these recommendations simply do not exist. The designation Xhtml 5 is in fact a surprising return to Xhtml roots, that can be explained by the equation : Xhtml 5 = Xml + Html 5.

Xhtml 1 and its Xml satellites encoutering difficulties to be popular because of the lazyness of some browsers, and Xhtml 2 having not meet the expected success, the W3c decided to go backward in proposing the Html 5 recommendation, which can be served under Xml form, i.e. Xhtml 5.

The working draft of Xhtml 5 is in fact not from the W3c, but from a consortium secretly created by browsers having rejected Xhtml 2. Thus, Firefox, Opera and Safari created the Whatwg, the informal working group of Xhtml 5. It is only during the presentation of the work produced by the Whatwg that the W3c understood that the Xhtml 5, pushed by browsers et answering to developpers and users whishes, would truly be the successor of Xhtml 1. The Xhtml 5 embed both the achievements of Html 4 and Xhtml 1, in cleaning their content and extending widely their possibilities, by the way of web forms 2.0 and the support of <canvas> element.