startList = function() {
  if (document.all&&document.getElementById) {
    navRoot = document.getElementById("nav_ul");
    assignMouseOvers(navRoot);
  }
}

function assignMouseOvers(navRoot) {
  //alert(navRoot.childNodes.length+"\n"+navRoot.innerHTML);
  for (var i=0; i<navRoot.childNodes.length; i++) {
    node = navRoot.childNodes[i];
    if (node.nodeName=="LI") {
      node.onmouseover=function() {
        this.className+=" over";
      }
      node.onmouseout=function() {
        this.className=this.className.replace(" over", "");
      }
      //alert(node.childNodes.length);
      for (var j=0; j<node.childNodes.length; j++) {
        subNode = node.childNodes[j];
        if (subNode.nodeName=="UL") {
          assignMouseOvers(subNode);
          //alert(subNode.childNodes.length);
        }
      }
    }
  }
  return;
}

window.onload=startList;