startList = function() {
var menuRoot = document.getElementById("menu").getElementsByTagName("li");;
for (var i=0; i<menuRoot.length; i++) {
 menuRoot[i].onmouseover=function() {
 this.className+=(this.className.length>0? " ": "") + "over";
 }
 menuRoot[i].onmouseout=function() {
 this.className=this.className.replace("over", "");
 }
 }
}
window.onload = startList;