Building according to web standards: Extensible Markup Language (XML) 1.0

XML is a markup language, like HTML. Rather than being restricted to one set of rules, it is a markup language for describing a markup language.

In practice, this gives you an opportunity to write a markup language appropriate to the information you are trying to structure. Examples of such applications include MathML (Math Markup Language) and SVG (Scalable Vector Graphics). Likewise, XML applications are found in offline applications.

Support for XML applications in web browsers is still limited. XML does however have highly interesting applications on the web server side. At present, XML is much used for databases, search engines and web services.

This manual will not cover writing your own markup language. A number of existing applications of XML will be discussed, however, for example, XHTML and RSS Syndication.