var _id = "subnav";
function initFirstLast() {
	var _list = document.getElementById(_id);
	var _nodes = _list.getElementsByTagName("li");
	for (var i = 0; i < _nodes.length; i++) {
		if(i == 0) {
			_nodes[i].className += "first";
		} else if (i == (_nodes.length - 1)) {
			_nodes[i].className += "last";
		} else {
			continue;
		}
	}
}
if (window.addEventListener) window.addEventListener("load", initFirstLast, false);
else if (window.attachEvent) window.attachEvent("onload", initFirstLast);