Definition
DOM Standard defines TreeWalker
[Exposed=Window]
interface TreeWalker {
[SameObject] readonly attribute Node root;
readonly attribute unsigned long whatToShow;
readonly attribute NodeFilter? filter;
attribute Node currentNode;
Node? parentNode();
Node? firstChild();
Node? lastChild();
Node? previousSibling();
Node? nextSibling();
Node? previousNode();
Node? nextNode();
};