Change this point to understand

First of all , We know return You can change this Point to

function Fn(name){ this.name=name; return {};//undefined, Changed the this The direction of , Point to the undefined object } var fn=new Fn(“maomin”); console.log(fn.name);

The other is our common method , Is to give this Assign to a variable .

function fn1(age) { var that=this; that.age=age; console.log(this.age)//21 } fn1(“21”);

But the above method is too low 了 . Next, let's talk about change this Three methods of pointing high ：

call()
(1) Anonymous functions can be changed this Point to 
12

Copy

var box=document.querySelector("#box"); box.onclick = function(){ 　　(function(){ 　　　　console.log(this); //box 　　}).call(this); };

(2) You can inherit methods

function Fn8(name,girlfriend) { this.name=name; this.girlfriend=girlfriend; } function Fn9(name,girlfriend) { Fn8.call(this,name,girlfriend);// The first one is an object , It's the object you want to borrow , In addition to the first parameter, the following parameters are passed into the function as actual parameters . console.log(this.name,this.girlfriend);//maomin, xqm } var fn9=new Fn9(“maomin”,“xqm”);

More on ：https://blog.csdn.net/weixin_44519496/article/details/120127993