jquery datatable按图像排序

<table id="myTable">
  <thead>
    <tr>
      <th>名称</th>
      <th>图片</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>产品A</td>
      <td class="image-sort"><img src="imageA.jpg" alt="产品A"></td>
    </tr>
    <tr>
      <td>产品B</td>
      <td class="image-sort"><img src="imageB.jpg" alt="产品B"></td>
    </tr>
    <tr>
      <td>产品C</td>
      <td class="image-sort"><img src="imageC.jpg" alt="产品C"></td>
    </tr>
  </tbody>
</table>

$(document).ready(function() {
  $('#myTable').DataTable({
    columnDefs: [
      { type: 'image-sort', targets: 1 }
    ]
  });
});

$.fn.dataTable.ext.order['image-sort-pre'] = function(data) {
  return $(data).find('img').attr('alt');
};