如何在固定标题的DataTable中添加多选过滤器？

<table id="myTable">
  <thead>
    <tr>
      <th>姓名</th>
      <th>年龄</th>
      <th>性别</th>
    </tr>
  </thead>
  <tbody>
    <!-- 表格数据行 -->
  </tbody>
</table>

$(document).ready(function() {
  $('#myTable').DataTable({
    initComplete: function() {
      this.api().columns().every(function() {
        var column = this;
        var select = $('<select><option value=""></option></select>')
          .appendTo($(column.header()).empty())
          .on('change', function() {
            var val = $.fn.dataTable.util.escapeRegex(
              $(this).val()
            );
            column
              .search(val ? '^' + val + '$' : '', true, false)
              .draw();
          });

        column.data().unique().sort().each(function(d, j) {
          select.append('<option value="' + d + '">' + d + '</option>');
        });
      });
    }
  });
});