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