XHTML (EXtensible HyperText Markup Language)

Extensible Hypertext Markup Language (XHTML)is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated. While HTML, prior to HTML5, was defined as an application of Standard Generalized Markup Language (SGML), a flexible markup language framework, XHTML is an application of XML, a more restrictive subset of SGML. XHTML documents are well-formed and may therefore be parsed using standard XML parsers, unlike HTML, which requires a lenient HTML-specific parser. XHTML 1.0 became a World Wide Web Consortium (W3C) recommendation on January 26, 2000. XHTML 1.1 became a W3C recommendation on May 31, 2001. The standard known as XHTML5 is being developed as an XML adaptation of the HTML5 specification.

Features of XHTML

• Unlike HTML, which is standard generalized markup language based, XHTML is XML-based.
• Compared to the rules of HTML, XHTML is stricter and does not allow any lapses in coding or structure. It prohibits the omission of any tags or usage of attribute minimization. All elements in XHTML must have a starting or ending tag.
• It is a restrictive subset of XML and needs to be parsed with help of standard XML parsers.
• XHTML documents has only one root element.
• As they are XML conforming, XHTML documents are easily viewed edited using standard XML tools.
• Unlike HTML, XHTML provides a more cleaner, consistent and well-structured format which helps in making the webpages easily parseable for present and future browsers.
• Sustainability is more pronounced in case of XHTML than HTML.
• As the error processing routines are shorter, future browsers can support faster processing of XHTML documents.
• As XHTML can support wide range of applications, using the same complex websites can be created.
• XHTML elements needs to be nester properly and should always be in lower case.

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