function initNav()
{
	var _menu = document.getElementById("nav");
	if(_menu) {
		var _items = _menu.getElementsByTagName("li");
		if(_items) {
			_items[0].className += " first";
			_items[_items.length-1].className += " last";
		}
	}
}

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