if (document.getElementById && document.getElementsByTagName)
  window.onload=function() {    
    navRoot = document.getElementById("menu").firstChild;
    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", "");
        };
      }
    }
  };