var sfHover = function() {

	if (!document.getElementsByTagName) return false;

	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);