The xsl:value-of tag is instantiated to create a text node in the result
tree. The select attribute is an Expression; this expression is
evaluated and the resulting object is converted to a string as if by a call to
the string function.The string specifies the string-value of the created text
node.No text node will be created, if the string is empty. The created text
node will be merged with any adjacent text nodes.
without converting it to a string the xsl:copy-of element can be used to copy a node-set over to the result tree.
The following example creates an HTML paragraph from a person element with
given-name and family-name attributes.The paragraph will contain the value of
family-name attribute of the current node and the given-name attribute of the current node followed by a space.