startList = function() {
var menu_items = document.getElementById("top-menu").getElementsByTagName("li");

   for (i=0; i < menu_items.length; i++) {
      if (menu_items[i].getElementsByTagName("ul").length > 0) {
         menu_items[i].onmouseover = function() {
            this.getElementsByTagName("a")[0].style.backgroundColor = "#336799";
            this.getElementsByTagName("ul")[0].style.display = "block";
         }
         
         menu_items[i].onmouseout = function() {
            this.getElementsByTagName("a")[0].style.backgroundColor = "transparent";
            this.getElementsByTagName("ul")[0].style.display = "none";
         }
      }
   }
} 

window.onload = startList;