XML in a Nutshell, 3rd Edition

xsl:stylesheet and xsl:transform

An XSLT stylesheet is an XML document. It can and generally should have an XML declaration. It can have a document type declaration, although most stylesheets do not. The root element of this document is either stylesheet or transform ; these are synonyms for each other, and you can use either. They both have the same possible children and attributes. They both mean the same thing to an XSLT processor.

The stylesheet and transform elements, like all other XSLT elements, are in the http://www.w3.org/1999/XSL/Transform namespace. This namespace is customarily mapped to the xsl prefix so that you write xsl:transform or xsl:stylesheet rather than simply transform or stylesheet.

Warning

This namespace URI must be exactly correct. If even so much as a single character is wrong, the stylesheet processor will output the stylesheet itself instead of either the input document or the transformed input document. There’s a reason for this (see Section 2.3 of the XSLT 1.0 specification, Literal Result Element as Stylesheet, if you really want to know), but the bottom line is that this weird behavior looks very much like a bug in the XSLT processor if you’re not expecting it. If you ever do see your stylesheet processor spitting your stylesheet back out at you, the problem is almost certainly an incorrect namespace URI.

In addition to the xmlns:xsl attribute declaring this prefix mapping, the root element must have a version attribute with the value 1.0. Thus, ...