showMenu = function() {

      var subMenuItems = document.getElementById("topMenu").getElementsByTagName("li");

      for (var i=0; i<subMenuItems.length; i++) {

      subMenuItems[i].onmouseover=function() {

      this.className+=" showMenu";

      }

      subMenuItems[i].onmouseout=function() {

      this.className=this.className.replace(new RegExp(" showMenu\\b"), "");

      }

      }

      }

      if (window.attachEvent) window.attachEvent("onload", showMenu);