Question

我有一个下拉列表，必须填充ajax响应。我在下拉列表中获得了额外的未定义选项。

频率下拉：

<div class="form-group">
        <label class="control-label col-xs-3" for="frequenies">Frequencies:</label>
        <div class="col-xs-9">
            <select name="frequencies" id="frequencies-list" class="form-control">
               <option value="">Select an option</option>
            </select>          
        </div>
</div>

Ajax响应：

success: function(data){
       alert(data);
       var x = JSON.parse(data);
       $.each(x, function() {
            $.each(this, function(k, v) {
              var frequencies = "<option value="+v.freq+">"+v.freq+"</option>";
              $(frequencies).appendTo('#frequencies-list');
           });
        });
}

数据变量是编码的JSON：

[[{"freq":"1"},{"freq":"3"},{"freq":"6"},{"freq":"12"},{"freq":"24"},{"freq":"36"},{"freq":"48"},{"freq":"60"},{"freq":"72"},{"freq":"96"},{"freq":"120"},{"freq":"144"}],[{"ad_size_full":"Tab Page"},{"ad_size_full":"BRC's"},{"ad_size_full":"Cover tip"}],[{"ad_size_fractional":"2\/3 Page"},{"ad_size_fractional":"1\/2 Page Island"},{"ad_size_fractional":"1\/2 Page"},{"ad_size_fractional":"1\/3 Page"},{"ad_size_fractional":"1\/4 Page"},{"ad_size_fractional":"1\/6 Page"}],[{"color":"B&W"},{"color":"2 Color"},{"color":"3  Color \/ 4 color"},{"color":"5 Color"},{"color":"Matched Color"},{"color":"Matalic Color \/ PMS 800"}],[{"charge":"0.000000"},{"charge":"0.250000"},{"charge":"0.100000"},{"charge":"0.500000"},{"charge":"0.150000"},{"charge":"0.150000"},{"charge":"0.100000"}]]

v.freq在我的下拉列表中生成额外的“未定义”选项。我可以帮忙吗？

1
3
6
12
24
36
48
60
72
96
120
144
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined
undefined

Answer 1

在下一个子array中，没有索引freq。试试 -

    $.each(x, function() {
        $.each(this, function(k, v) {
          if (typeof v.freq != 'undefined') {
              var frequencies = "<option value="+v.freq+">"+v.freq+"</option>";
              $(frequencies).appendTo('#frequencies-list');
          }
       });
    });

或仅遍历第一个子阵列。

Answer 2

或者简单地说：

   $.each(x, function() {
            $.each(this, function(k, v) {
              if (v.freq) // will check for undefined, null, isNaN
               {
                  var frequencies = "<option value="+v.freq+">"+v.freq+"    </option>";
                  $(frequencies).appendTo('#frequencies-list');
              }
           });
        });

Answer 3

你需要的只是频率对吗？怎么样这样：

$.each(x, function() {
    $.each(this, function(k, v) {
      if ("freq" in v) {
          var frequencies = "<option value="+v.freq+">"+v.freq+"</option>";
          $(frequencies).appendTo('#frequencies-list');
      }
   });
});

Answer 4

尝试使用对象的第一个元素循环内部循环。

$.each(x, function() {
                $.each(x[0], function(k, v) {
                      var frequencies = "<option value="+v.freq+">"+v.freq+"</option>";
                      $(frequencies).appendTo('#frequencies-list');
               });
            });

JSON检索中选择框的额外未定义选项

4 个答案: