sfHover = function () {
   var sfEls = document.getElementById("dropdown-nav").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);