Read parentNode to access the node's parent node, if it exists. If the node does not have a parent node, the value of parentNode is nil (Delphi) or NULL (C++). 

Nodes of type ATTRIBUTE_NODE, DOCUMENT_NODE, and DOCUMENT_FRAGMENT_NODE never have parents. Nodes of type ENTITY_NODE and NOTATION_NODE may not have a parent. Nodes of other types have a parent unless they have just been created but not yet added to the hierarchy, or if they have just been removed from the hierarchy. 

nodeType