## 1、Child.prototype = new Parent()取不到Child原型上的属性，constructor指向Parent
//父类
function Parent(){
    this.name = "P_Name";
}
Parent.prototype.func=function(){
    console.log("Parent Func");
}
//子类
function Child(){
}
Child.prototype=new Parent();

Child.prototype.func = function(){
    console.log("Child Func");
}
var child = new Child;
var parent = new Parent;

child.func();//Child Func
console.log(child.name);//P_Name
console.log(Child.prototype.constructor) // Parent
parent.func();//Parent Func
## 2、Child.prototype = Parent.prototype取不到Parent的构造函数属性，constructor指向Parent,而且对子类的原型方法重写会使父类的原型方法被重写
function Child2(){
}
# 以下赋值将覆盖Parent.prototype.func方法
Child2.prototype=Parent.prototype;

Child2.prototype.func = function(){
    console.log("Child2 Func");
}

var child2 = new Child2;
child2.func();//Child2 Func
console.log(child2.name);//undefined
console.log(Child2.prototype.constructor) // Parent
parent.func();//Child2 Func

function Animal (name,sound) {
        this.name = name
        this.sound = sound
    }
    
    Animal.prototype.shout = function () {
        console.log(this.name + this.sound)
    }
    
    let dog = new Animal(‘pipi‘,‘wang!wang!‘)
    
    // 定义Plants
    function Plants (name) {
        this.name = name
        this.sound = null
    }
    
    // 函数接收参数用于区分
    Plants.prototype.shout = function (xssss) {
        console.log(this.name + this.sound +‘plants tag‘)
    }
    
    Plants.prototype.genO2 = function () {
        console.log(this.name + ‘生成氧气。‘)
    }

 Animal.prototype = Object.create(Plants.prototype)
    console.log(Animal.prototype)
    /*
    Plants {}
        __proto__:
            shout: ? (xssss)
            genO2: ? ()
            constructor: ? Plants()
            __proto__: Object
    */
    let cat = new Animal(‘mimi‘,‘miao~miao~‘)
    
    dog.shout() // pipi wang!wang!
    cat.shout() // mimi miao~miao~ plants tag
    cat.genO2() // mimi 生成氧气。

   Object.setPrototypeOf(Animal.prototype,Plants.prototype)
    console.log(Animal.prototype)
    /*
    Plants {shout: ?, constructor: ?}
        shout: ? (xssss)
        constructor: ? Animal(name,sound)
        __proto__:
        shout: ? ()
        genO2: ? ()
        constructor: ? Plants()
        __proto__: Object
    */
    dog.shout() // pipi wang!wang!
    cat.shout() // mimi miao~miao~
    cat.genO2() // mimi 生成氧气。