Acronym for Extensible HyperText Mark-up Language (XHTML) is a reformation of HTML as an XML vocabulary. This is a good idea, as it eliminates a lot of the problems that arose from the existence of proprietary or badly coded HTML , because it must now follow the strict rules of XML . XHTML is an XML application that specifies how XML can be used to describe a web page. XHTML documents look very similar to HTML documents, except they follow the rules of XML (which include things like all tags must have a matching closing tag, attributes must be quoted, tags must be nested properly and there must be a root tag for the overall document). XHTML is a subset of XML , but XML is not a subset of XHTML.The ultimate goal of using XHTML is to separate display/presentation tags from the document data/structure and to use the elements as they were meant to be used. The key change to make, is separating presentation from content.

Acronym for Extensible Markup Language (XML) is a language specification from the W3C that allows users to develop their own markup languages (often called vocabularies), and format their documents using stylesheets to be presented on a browser if desired. It is a syntax/format, establishing rules for XML -compliant languages with a very strict set of rules that must be adhered to, allowing lots of control over document format.

Acronym for eXtensible Object Oriented Portal System. XOOPS is a program that allows administrators to easily create dynamic websites with great content and many outstanding features. It is an ideal tool for developing small to large dynamic community websites, intra company portals, corporate portals, weblogs and much more. It can be installed on an Internet host with a PHP-capable web server (e.g., Apache) and a database (e.g., MySQL).

Acronym for Extensible Style Language (XSL) is a W3C specification that contains 3 parts. Extensible Stylesheet Language Transformations (XSLT) for changing the formatting and structure of markup according to a set of rules, Extensible Stylesheet Language Formatting Objects (XSL-FO) for applying a strong set of rules to a document to ensure reliable formatting when printed, and XPath to select the elements required by an XSLT.