sfHover = function() {
  if (document.getElementById("mainmenu")) {
  	var sfEls = document.getElementById("mainmenu").getElementsByTagName("LI");
  	for (var i=0; i<sfEls.length; i++) {
  		sfEls[i].onmouseover=function() {
  			this.className+=" over";
  		}
  		sfEls[i].onmouseout=function() {
  			this.className=this.className.replace(new RegExp(" over\\b"), "");
  		}
  	}
  }
}
if (window.attachEvent) window.attachEvent("onload", sfHover);