sfHover = function() {
    if (document.getElementById("nav") != null)
    {
        var navArray = document.getElementById("nav").getElementsByTagName("li");
       
        for (i=0; i<navArray.length; i++) {
                navArray[i].onmouseover=function() {
                      this.className+=" over";
                }
                navArray[i].onmouseout=function() {
                      this.className=this.className.replace(" over", "");
                }
        }
    }
}
if (window.attachEvent) window.attachEvent("onload", sfHover);