The DocumentTraversal object is defined in the Traversal module of the W3C DOM, where it defines the createNodeIterator( ) and createTreeWalker( ) methods. These methods (and the otherwise invisible DocumentTraversal interface) are blended into the document object so that scripts can access them (only the document.createTreeWalker( ) method is implemented in Netscape 7, but createNodeIterator( ) is sure to follow).