- Define a parent constructor
- Then define a sub-constructor
- Constructors sub inherit the parent constructor attributes (using the method call)
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// 借用父构造函数继承属性
// 1. 父构造函数
function Father(uname, age) {
// this 指向父构造函数的对象实例
this.uname = uname;
this.age = age;
}
Father.prototype.money = function() {
console.log(100000);
};
// 2 .子构造函数
function Son(uname, age, score) {
// this 指向子构造函数的对象实例
Father.call(this, uname, age);
this.score = score;
}
// 这样直接赋值会有问题,如果修改了子原型对象,父原型对象也会跟着一起变化
Son.prototype = Father.prototype;
Son.prototype = new Father();
// 如果利用对象的形式修改了原型对象,别忘了利用constructor 指回原来的构造函数
Son.prototype.constructor = Son;
// 这个是子构造函数专门的方法 【子构造函数专门的方法 要写在上面两行代码的后面。】
Son.prototype.exam = function() {
console.log('孩子要考试');
}
var son = new Son('刘德华', 18, 100);
console.log(son); // (1)有money、exam方法; (2)Son {uname: "刘德华", age: 18, score: 100}
console.log(Father.prototype); // (1)有money方法，没有exam方法; (2){money: ƒ, constructor: ƒ}
console.log(Son.prototype.constructor); //
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</html>The results are shown as Code:
