javascript - jQuery .change 事件不会在多个相同的类上触发

Question

HTML 代码:

$(".imageupload").change(function() {
  alert($(this).attr('data-id'));
  var ID = $(this).attr('data-id');

  if (typeof(FileReader) != "undefined") {

    var image_holder = $("#image-holder" + ID);
    image_holder.empty();

    var reader = new FileReader();
    reader.onload = function(e) {
      $("<img />", {
        "src": e.target.result,
        "class": "thumb-image"
      }).appendTo(image_holder);

    }
    image_holder.show();
    reader.readAsDataURL($(this)[0].files[0]);
  } else {
    alert("This browser does not support FileReader.");
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="col-sm-6 col-md-3">
  <div id="image-holder1" style="margin-bottom:20px"> </div>
  <input type="file" class="input-file full-width imageupload" data-id="1" name="imageupload1" id="imageupload1" value="" placeholder="">
  <div id="displayimagefield">
    <div id="image-holder2" style="margin-bottom:20px"> </div>
    <input type="file" class="input-file full-width imageupload" data-id="2" name="imageupload2" id="imageupload2" value="" placeholder="">
    <div id="image-holder3" style="margin-bottom:20px"> </div>
    <input type="file" class="input-file full-width imageupload" data-id="3" name="imageupload3" id="imageupload3" value="" placeholder="">
  </div>
</div>

类 imageupload 位于多个元素中。更改事件仅在 data-id="1"中触发，不在其他任何地方触发。我该如何解决这个错误？抱歉我的英语不好。

Answer 1

使用事件委托(delegate)将附加事件动态添加的元素:

$("body").on('change','.imageupload',function() {
    //CHANGE EVENT CODE HERE
});