idref

The idref() function performs the inverse operation to the id() function: it locates all the nodes in a document that contain IDREF or IDREFS values referencing a given ID value.

Argument	Data Type	Meaning
Target	xs:string*	A sequence of ID values. The function finds all element and attribute nodes of type IDREF or IDREFS that contains a reference to at least one of the ID values in this argument
document (optional)	node()	A node identifying the document in which the IDREFS) values are to be located. If omitted, the document containing the context node is used
Result	node()*	The element and attribute nodes that were found, in document order, without duplicates