"Uncaught TypeError: Cannot use 'in' operator to search for 'length' in" when getting checked values by data attribute

Question

这是复选框组的视图

这是我的html上面视图的代码（还有更多复选框，这里只提到2个）：

    <div class="panel-body subject_names">
   <div class="col-md-12">
      <label for="checkboxes-0" class="col-md-7">
      KE1-Financial Accounting &amp; Reporting Fundamen
      </label>
      <input type="checkbox" data-subject-name="KE1-Financial Accounting &amp; Reporting Fundamen" data-subject-ai="925" class="big-checkbox col-md-1 subject1" name="exam_subjects" id="checkboxes-0" value="1012"> 
      <div class="col-md-4 pull-left">
         <input id="training_institute" name="textinput" type="text" placeholder="" class="input-md">
      </div>
   </div>

   <div class="col-md-12">
      <label for="checkboxes-0" class="col-md-7">
      KE2-Management Accounting Information
      </label>
      <input type="checkbox" data-subject-name="KE2-Management Accounting Information" data-subject-ai="926" class="big-checkbox col-md-1 subject1" name="exam_subjects" id="checkboxes-0" value="1013"> 
      <div class="col-md-4 pull-left">
         <input id="training_institute" name="textinput" type="text" placeholder="" class="input-md">
      </div>
   </div>


</div>

这是我的 js 代码：

var subjects_names = [];
$.each($("input[name='exam_subjects']:checked").attr("data-subject-name"), function() {
    subjects_names.push($(this).val());
});

异常：

Exam_application_c:775 Uncaught TypeError: Cannot use 'in' operator to search for 'length' in KE1-Financial Accounting & Reporting Fundamen

Answer 1

您在 string 上使用 $.each，它必须是 object 或 array。

尝试将您的代码更改为此

var subjects_names = [];
$.each($("input[name='exam_subjects']:checked"), function () {
    subjects_names.push($(this).data("subjectName"));
});

或者更好的是使用 .each 作为对 jQuery 对象的迭代

var subjects_names = [];
$("input[name='exam_subjects']:checked").each(function () {
    subjects_names.push($(this).data("subjectName"));
});

"Uncaught TypeError: Cannot use 'in' operator to search for 'length' in" when getting checked values by data attribute

"Uncaught TypeError: Cannot use 'in' operator to search for 'length' in" when getting checked values by data attribute

javascript

arrays

checkbox

checkboxlist