var 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);