Javascript回调丢失“this” [英] Javascript callbacks losing 'this'

问题描述

我有一个签发者，我在这个'对象'里面失去了'这'。下面的javascript的输出给我some-id，然后未定义。当我在回调函数中使用'this'时，作用域将退出对象，不再使用'this'。如何获取回调以使用this或至少可以访问对象？

I have an issuer where I lose the 'this' inside this 'object'. The output of the following piece of javascript gives me "some-id" and then "undefined". When I use 'this' inside a callback function, the scope goes out of the object and it cannot use 'this' anymore. How can I get the callback to use 'this' or at least have access to the object?

由于我将创建多个对象，我将无法创建一个静态的存储。请帮助这个javascript n00b; - ）

Since I will make multiple objects, I won't be able to create a 'static' like storage. Please help this javascript n00b ;-)

这里是我的测试代码，你可以用来重现我的问题。我想要的是 CheckBox.doSomething（）返回 this.id 的值应该匹配 some-id 。

here is my test code that you can use to reproduce my problem. What I would like to have is CheckBox.doSomething() to return the value of this.id which should match some-id for this test case.

function CheckBox(input_id) {
    this.id = input_id;
    this.doSomething();
    $('#some-element').click(this.doSomething);
}

Checkbox.prototype.doSomething = function() {
    alert(this.input_id);
}

var some_box = new CheckBox('some-id');
some_box.doSomething();
$('#some-element').click();

编辑：我甚至无法使其工作，因为我想要：

edit: I can't even get this to work as I want it to:

function CheckBox2(input_id) {
    this.id = input_id;
    alert(this.id);
}

CheckBox2.prototype.doSomething = function() {
    alert(this.input_id);
}
var some_box = new CheckBox2('some-id');
some_box.doSomething();

推荐答案

function CheckBox(input_id) {
    this.id = input_id;
    this.doSomething = $.proxy( this.doSomething, this );
    $('#some-element').click(this.doSomething);
}

bind 但是这不是在每个浏览器都可用，并且似乎你使用jQuery我使用jQuery等效 $。proxy

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