火狐官网上找到的一组函数,相当于treeWalker,有了它可以方便地在IE实现Traversal API 2的所有功能(nextElementSibling,previousElementSibling,firstElementChild,lastElementChild,children)These functions let you find the next sibling, previous sibling, first child, and last child of a given node (element). What makes them unique is that they safely ignore whitespace nodes so you get the real node you're looking for each time.