The Extensible Markup Language is a strict serialization of the Document Object Model.

EXSLT

EXSLT is a set of extensions to XSLT organized into modules that provide functions for performing transformations on an XML document. To use an EXSLT function, you need to declare the namespace the function is in, and then use the appropriate prefix when calling the function.

XML Guides

This page lists guides for XML.

XPath

XPath stands for XML Path Language. It uses a non-XML syntax to provide a flexible way of addressing (pointing to) different parts of an XML document. It can also be used to test addressed nodes within a document to determine whether they match a pattern or not.

XSLT: Extensible Stylesheet Language Transformations

Extensible Stylesheet Language Transformations (XSLT) is an XML-based language used, in conjunction with specialized processing software, for the transformation of XML documents.