组合继承

//组合继承:原型继承+借用构造函数继承

function Person(name,age,sex) {
    this.name=name;
    this.age=age;
    this.sex=sex;
}
Person.prototype.sayHi=function () {
    console.log("阿涅哈斯诶呦");
};
function Student(name,age,sex,score) {
    //借用构造函数:属性值重复的问题
    Person.call(this,name,age,sex);
    this.score=score;
}
//改变原型指向----继承
Student.prototype=new Person();//不传值
Student.prototype.eat=function () {
    console.log("吃东西");
};
//此时的"小黑",20,"男","100分" 都是属于对象的信息，不是原型的信息
var stu=new Student("小黑",20,"男","100分");
console.log(stu.name,stu.age,stu.sex,stu.score);
stu.sayHi();
stu.eat();
var stu2=new Student("小黑黑",200,"男人","1010分");
console.log(stu2.name,stu2.age,stu2.sex,stu2.score);
stu2.sayHi();
stu2.eat();
//属性和方法都被继承了
//推荐使用