The id function finds nodes matching the given ids and returns a node-set containing the identified nodes.
id( expression )
expressionIf expression is a node-set, then the string value of each node in the node-set is treated as an individual id. The returned node set is the nodes corresponding to those ids. If expression is a string, or anything other than a node-set, then expression is treated as a space-separated list of ids. The returned node set is the nodes corresponding to those ids.
A node-set containing the node or nodes identified by the given id or ids.
Partially supported.