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