$(function(){
	firstLast();
});
function firstLast() {
	var tools = {
		hasClass: function(obj,cname) {
			return (obj.className ? obj.className.match(new RegExp('(\\s|^)'+cname+'(\\s|$)')) : false);
		},
		addClass: function (obj,cname) {
			if (!tools.hasClass(obj,cname)) {obj.className += " "+cname;tools.accurateRecordClass(obj)}
		},
		removeClass: function(obj,cname) {
			if (tools.hasClass(obj,cname)) {obj.className=obj.className.replace(new RegExp('(\\s|^)'+cname+'(\\s|$)'),' ');tools.accurateRecordClass(obj)}
		},
		accurateRecordClass: function (obj) {
			if (obj.className) obj.className = obj.className.replace(/(^\s+|\s+$)/g, '');
		}
	
	}
	var sets = document.getElementById('nav');
	if (sets) {
		var lists = sets.getElementsByTagName("li");
		var _array = [];
		for (var j = 0; j < lists.length; j++) {
			if (lists[j].parentNode == sets) {
				_array.push(lists[j]);
			}
		}
		if (_array.length > 1) {
			tools.addClass(_array[0], 'first');
			tools.addClass(_array[_array.length - 1], 'last');
		}
	}
}