startList = function() {
   if (document.all&&document.getElementById) {
       navRoot = document.getElementById("nav");

       for (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", "");
                }
            }
       }

   }

}

window.onload=startList;