js寄生函数

// 寄生函数function obj(o){function Fn(){};Fn.prototype = o;    // 把指针转回给自己return new Fn();}function create(o,oBj){var _o = obj(o.prototype);_o.constructor = oBj;oBj.prototype = _o;return _o;}function B(name,age){this.name = name;this.age = age;}B.prototype.run = function(){return this.name + this.age;}function D(name,age){B.call(this,name,age);}create(B,D);var box = new D('gaga',236);console.log(box.constructor)