//寄生函数
function create(box, desk) {//继承私有的属性和prototype中的属性
	var f = obj(box.prototype);
	f.constructor = desk;				//调整原型构造指针
	desk.prototype = f;
}

function Box(name, age) {
	this.name = name;
	this.age = age;
}

Box.prototype.run = function () {
	return this.name + this.age + '运行中...'
}

function Desk(name, age) {
	Box.call(this, name, age);				//对象冒充
}

//通过寄生组合继承来实现继承
create(Box, Desk);							//这句话用来替代Desk.prototype = new Box();


var desk = new Desk('Lee', 100);
alert(desk.run());
alert(desk.constructor);