function F1(age) { this.age = age; } function F2(age) { this.age = age; } F2.prototype = new F1(10); function F3(age) { this.age = age; } F3.prototype = new F2(20); var f3 = new F3(30); console.log(f3.age);//
原文：https://www.cnblogs.com/jane-panyiyun/p/12157765.html