|The xsl:copy-of element can be used to insert a result tree fragment into the result tree, without first converting it to
a string as xsl:value-of does (see [7.6.1 Generating Text with xsl:value-of]). The required select attribute contains an expression.
When the result of evaluating the expression is a result tree fragment, the complete fragment is copied into the result tree.
When the result is a node-set, all the nodes in the set are copied in document order into the result tree; copying an element
node copies the attribute nodes, namespace nodes and children of the element node as well as the element node itself; a root
node is copied by copying its children. When the result is neither a node-set nor a result tree fragment, the result is converted
to a string and then inserted into the result tree, as with xsl:value-of.
Examples (xslt:xml): Overview