var jshover = function() {
 var sfEls = document.getElementById("topmenu").getElementsByTagName("li");
 for (var i=0; i<sfEls.length; i++)
 {
 sfEls[i].onmouseover=function()
 {
 this.className+=" jshover";
 }
 sfEls[i].onmouseout=function()
 {
 this.className=this.className.replace(new RegExp(" jshover\\b"), "");
 }
 }
}

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