Question

我正在尝试从对象中引用discount_code属性，但是我一直收到以下错误。我如何访问discount_code？

错误：

未捕获的TypeError：无法调用未定义的方法'val'

HTML：

<input type="text" name="txt_discount_code" value="12345" />

JS：

var cart = {
    transaction: {},
    discount_code: $('input[name=txt_discount_code]'),

    get_cart_items_params: {
        page: 'checkout',
        s_method: 'get-cart-items',
        txt_discount_code: this.discount_code.val()
        // txt_discount_code: cart.discount_code.val()
    }
};

Answer 1

与ShankarSangoli类似，您无法在定义对象之前访问该对象。

你必须将cart的声明分成两部分：

var cart = {
    transaction: {},
    discount_code: $('input[name=txt_discount_code]')
};

cart.get_cart_items_params = {
    page: 'checkout',
    s_method: 'get-cart-items',
    txt_discount_code: cart.discount_code.val()
};

或者只是将discount_code放入变量：

var $discount_code = $('input[name=txt_discount_code]');
var cart = {
    transaction: {},
    discount_code: $discount_code
    get_cart_items_params = {
        page: 'checkout',
        s_method: 'get-cart-items',
        txt_discount_code: $discount_code.val()
    }
};

Answer 2

在完全定义之前，您无法使用该对象。它永远不会奏效。

Answer 3

我最初认为你的问题在你的jQuery选择器上撒谎，但在我用jQuery选择器替换静态值并尝试引用它仍然无效。我得出结论，在完成对象的创建之前，你不能引用discount_code：

查看FIDDLE

var cart = {
    transaction: {},

    get_cart_items_params: {
        page: 'checkout',
        s_method: 'get-cart-items',
        txt_discount_code: function(){
         return $('input[name="txt_discount_code"]').val();
        }
    }
};

cart.get_cart_items_params.txt_discount_code();

财产范围问题？

3 个答案: