实现jQuery的$.extend方法

var o1 = {
	hello : 1,
	old : 555
}, o2 = {
	abc : 55555555,
	hello : 2,
	fun : function() {
		alert(111);
	}
}, o3 = {
	third : 9999
};
function cloneObj(oldObj) {//复制对象方法
	if ( typeof (oldObj) != 'object')
		return oldObj;
	if (oldObj == null)
		return oldObj;
	var newObj = new Object();
	for (var i in oldObj)
	newObj[i] = cloneObj(oldObj[i]);
	return newObj;
};
function extendObj() {//扩展对象
	var args = arguments;
	if (args.length < 2)
		return;
	var temp = cloneObj(args[0]);
	//调用复制对象方法
	for (var n = 1; n < args.length; n++) {
		for (var i in args[n]) {
			temp[i] = args[n][i];
		}
	}
	return temp;
}

var t = extendObj(o1, o2, o3);
console.log(t);
console.log(o1);
console.log(o2);
console.log(o3);