Introduction

An XML DTD exists to describe the elements and attributes allowed in an XSLT stylesheet. XML editor software can use this DTD to provide a guided environment for the authoring of stylesheets. It can also be used by XML parsers to validate a stylesheet received from elsewhere. The DTD is listed in annex C of the standard. For those unfamiliar with XML DTDs, it is recommended that a book on XML be consulted before reading this chapter. Alternatively, Chapter 21 provides a brief overview of DTD markup.

The default DTD includes the prefix 'xsl:' on all XSLT element names, such as 'xsl:template'. This can be changed to whatever is appropriate (including no prefix at all if XSLT elements are assigned to the default namespace).