填充第二选择框-绑定问题 [英] Populating a 2nd select box - binding problem

问题描述

我正在使用以下代码在城市中填充第二个选择框:

I'm using the following code to populate a 2nd select box with cities:

  jQuery('#country').live("change", function(){ 
    populateCityListBox();
    alert(jQuery("select#city").val());
  }); 

- - - -  - - - - - - - - - - -

  function populateCityListBox()
  {

    jQuery.get("my/path/myfile.php", { instance: 'getCitiesByCountry', countryID: jQuery("select#country").val(), brandID: $_GET('brandID') },
      function(data)
      {
          var options = '';
          for (var i = 0; i < data.length; i++) {
            if (i == 0)
              options += '<option selected value="' + data[i].city + '">' + data[i].city + '</option>';
            else
              options += '<option value="' + data[i].city + '">' + data[i].city + '</option>';

          }

          jQuery("select#city").append(options);
      },"json");
  }

填充列表框效果很好.但是警报不会输出新城市(选择国家/地区后).这可以成为一个有约束力的问题吗?我以为使用$ .live解决了所有这一切.

Populating the list box works fine. But the alert does not output the new city (after country selection). Can this be a binding problem? I thought using $.live solved all this.

似乎在更新城市列表框之前已触发alert().我在做什么错了?

It looks like the alert() is triggered before the city list box is updated. What am I doing wrong?

推荐答案

史蒂文，您说得很对.代码:

Steven, you are exactly right. The code:

alert(jQuery("select#city").val());

在您的get()请求与服务器的响应一起返回之前正在执行.您定义的用于填充城市列表的回调函数在收到响应之前不会运行.

is executing before your get() request has returned with a response from the server. The callback function you defined for populating your city list doesn't run until a response is received.

尝试创建另一个函数来显示您的警报，然后从get的回调中对其进行调用:

Try creating another function to display your alert, and call that from the get's callback:

  jQuery('#country').live("change", function(){ 
    populateCityListBox();
  }); 

function showCity()
{
    alert(jQuery("select#city").val());
}

- - - -  - - - - - - - - - - -

  function populateCityListBox()
  {

    jQuery.get("my/path/myfile.php", { instance: 'getCitiesByCountry', countryID: jQuery("select#country").val(), brandID: $_GET('brandID') },
      function(data)
      {
          var options = '';
          for (var i = 0; i < data.length; i++) {
            if (i == 0)
              options += '<option selected value="' + data[i].city + '">' + data[i].city + '</option>';
            else
              options += '<option value="' + data[i].city + '">' + data[i].city + '</option>';

          }

          jQuery("select#city").append(options);
          showCity();
      },"json");
  }

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