怎樣實現構造函數的繼承

封裝/繼承/多態是面向對象編程的三個特征, js中實現構造函數的繼承需要分兩步實現: 

1. 在子類構造函數中調用父類的構造函數;

2. 讓子類的原型對象"復制"父類的原型對象;

下面是一個具體的例子: 

function Father(name){
    this.name = name;
}

function Son(name, age){
    Father.call(this, name);
    this.age = age;
}
Son.prototype = Object.create(Father.prototype);
Son.prototype.constructor = Son;

var lilei = new Son("Lilei", 23);
lilei.name; // "Lilei"
lilei.age; // 23
lilei.constructor === Son; // true