Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
745 views
in Technique[技术] by (71.8m points)

this 指向的问题

(function(){
    var a = 11111;
    console.log(this.a);    

    var Test = function(a){
        this.a = a;
    }
    Test.prototype.geta=function(){
        console.log(this.a)
        console.log(this);
    }
    var test = new Test('a');
    test.geta();      

    var getaaa = test.geta;
    getaaa();    

})()

图片描述
getaaa()中 this 指向的是 window 但是为什么 this.a 为什么是 undefined


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

因为题主没有在window上声明变量a,题主声明的变量在自执行函数里,属于自执行函数的局部变量,不属于window


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...