JavaScript原型与原型链深入探究使用方法

<script>
    console.log(Date.prototype, typeof Date.prototype);
    function fun(){
    }
    fun.prototype.test = function(){ //给原型对象添加一个方法
        console.log('test()');
    }
    console.log(fun.prototype); // 默认指向一个Object空对象(没有我们的属性)
</script>

<script>
    function fun(){
    }
    console.log(Date.prototype.constructor === Date);
    console.log(fun.prototype.constructor === fun);
</script>

<script>
    function fun(){
    }
    fun.prototype.test = function(){//给原型对象添加方法(属性)
        console.log('test()');
    }
    var fn = new fun()//函数的所有实例对象自动拥有原型中的方法(属性)
    fn.test()
</script>

<script>
    function fun(){
    }
    console.log(fun.prototype);
</script>

<script>
    function fun(){
    }
    var fn = new fun()
    console.log(fn.__proto__);
</script>

<script>
    function fun(){
    }
    // console.log(fun.prototype);
    var fn = new fun()
    // console.log(fn.__proto__);
    console.log(fun.prototype === fn.__proto__); //结果是 true
</script>

<script>
    console.log(Object.prototype.__proto__);
    function Fun(){
        this.test1 = function(){
            console.log('test1()');
        }
    }
    console.log(Fun.prototype);
    Fun.prototype.test2 = function(){
        console.log('test2()');
    }
    var fun = new Fun()
    fun.test1()
    fun.test2()
    console.log(fun.toString())
    fun.test3()
</script>

<script>
    function Fun(){
    }
    //函数的显示原型指向的对象默认是空 Object 实例对象(但 Object 不满足)
    console.log(Fun.prototype instanceof Object); 
    console.log(Object.prototype instanceof Object); 
    console.log(Function.prototype instanceof Object); 
    //所有函数都是 Function 的实例(包括 Function)
    console.log(Function.__proto__ === Function.prototype); 
    // Object 的原型对象是原型链的尽头
    console.log(Object.prototype.__proto__); 
</script>

<script>
    function Fun(){
    }
    Fun.prototype.a = 'xxx'
    var fun = new Fun()
    console.log(fun.a,fun);
    var fun1 = new Fun()
    fun1.a = 'yyy'
    console.log(fun.a,fun1.a,fun1);
    function Person(name,age){
        this.name = name
        this.age = age
    }
    Person.prototype.setName = function(name){
        this.name = name
    }
    var p1 = new Person('Tom',12)
    p1.setName('Bob')
    console.log(p1);
    var p2 = new Person('Jack',12)
    p2.setName('andy')
    console.log(p2);
    console.log(p1.__proto__ === p2.__proto__);
</script>

<script>
    function Fun(){}
    var fn = new Fun()
    console.log(fn instanceof Fun); 
    console.log(fn instanceof Object);
    console.log(Object instanceof Function);
    console.log(Object instanceof Object);
    console.log(Function instanceof Function);
    console.log(Function instanceof Object);
    function Foo(){}
    console.log(Object instanceof Foo);
</script>

<script>
    function A(){}
    A.prototype.n = 1
    var b = new A()
    A.prototype = {
        n:2,
        m:3
    }
    var c = new A()
    console.log(b.n, b.m, c.n, c.m);
</script>

<script>
    function F(){}
    Object.prototype.a = function(){
        console.log('a()');
    }
    Function.prototype.b = function(){
        console.log('b()');
    }
    var f = new F()
    f.a()
    F.a()
    F.b()
    console.log(f);
    console.log(Object.prototype);
    console.log(Function.prototype);
</script>