Question

我正在尝试在警报窗口中打印出person对象的名称值。

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我得到的结果是一个空的警告框。当我在名称中硬编码时，警报框正确打印。我试过say_name：alert（person.name），但返回一个未定义的。我做错了什么？

Answer 1

您需要为say_name分配一个功能。现在，您立即调用该函数并分配其undefined返回值。这使得this引用了除你期望之外的东西。

var person = {
    name: 'Tray',
    distance_travelled: 0,
    say_name: function() {
        alert(this.name);
    },
}

person.say_name();

现在this arg将引用person对象，因为当您执行some_object.someMethod()时，this中someMethod()的值会自动设置为调用它的some_object。

从警报窗口中的对象打印出值

1 个答案: