My Solution to TreeWalker

[Michael Wachsman]

nextNode = function(node) {

    if(node.childNodes.length) return node.firstChild; 

    if(node.nextSibling !== null) return node.nextSibling;

    while(node !== null && node.nextSibling === null){

       node = node.parentNode;

    }

    return node.nextSibling;

};