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