My solution to Tree Walker

[Jennifer Openshaw]

nextNode = function(node) {

  //...Code goes here to walk to the next node...

if (node.childNodes.length !== 0) {

  node = node.firstChild;

    } else if (node.nextSibling !== null) {

    node = node.nextSibling;

    } else if (node.parentNode.nextSibling !== null) {

      node = node.parentNode.nextSibling;

    } else {

    node = node.parentNode.parentNode.nextSibling;

    }

  return node;

};