XSLT

XSLT (eXtensible Stylesheet Language Transformations) is a language for transforming one XML document to another XML document.

The most common destination document is an XHTML document.

XSL Transformations - a language for transforming XML documents into other XML documents.

XSLT uses XPath to find information in an XML document

The root element of a XSLT document is either <xsl:transform> or <xsl:stylesheet>. These are equivalent. Therefore the header of an XSLT document will be:

<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

or

<xsl:transform version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

http://www.w3schools.com/xsl/