javascript - 新手求救：為什麼這裡的Console.log回傳undefined？

Question

function d(){this.get=function(){this.getNum()}};
d.prototype.getName=function(){return 3;} ;
var d = new d();
console.log(d.get());//undefined

為什麼這裡顯示undefined？而不是3？求解答

Answer 1

雷雷

Answer 2

function d(){this.get=function(){return this.getNum()}};

你說呢

Answer 3

function d(){this.get=function(){return this.getName();}};
d.prototype.getName=function(){return 3;};
var d = new d();
console.log(d.get());

自己對比下

Answer 4

名字

Answer 5

this.getnum改成this.getname

Answer 6

雷雷