function initZindex() {
	var sets = document.getElementsByTagName("ul");
	for (var i = 0; i < sets.length; i++)	{
		if (sets[i].className.indexOf("z-nav") != -1) {
			var lists = sets[i].getElementsByTagName("li");
			var list_len = lists.length;
			for (var j = 0; j < lists.length; j++) {
			 lists[j].style.zIndex = list_len;
			 list_len--;
			}
		}
	}
}

if (window.addEventListener) window.addEventListener("load", initZindex, false);
else if (window.attachEvent) window.attachEvent("onload", initZindex);