serialize(node, format)
This function takes two arguments: the first is a node (generally a document or element node)
to be serialized. The second is the name of an xsl:output
element in the stylesheet.
The second argument must be known at compile time (it will typically be supplied as a string literal.)
The function serializes the specified document, or the subtree rooted at the specified element, according
to the parameters specified in the named xsl:output
element, and returns the serialized
document as a string.
This function is useful where the XSLT stylesheet wants to manipulate the serialized output, for example by embedding it as CDATA inside another XML document, or prefixing it with a DOCTYPE declaration, or inserting it into a non-XML output file.