在jquery datatables插件的下拉过滤器中获取'All‘选项

<select id="filter">
  <option value="">All</option>
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

$(document).ready(function() {
  $('#example').DataTable({
    // datatables配置项
    initComplete: function() {
      var api = this.api();
      var select = $('#filter');

      select.on('change', function() {
        var selectedValue = $.fn.dataTable.util.escapeRegex(
          $(this).val()
        );

        api.column(0)
          .search(selectedValue === '' ? '^' : selectedValue + '$', true, false)
          .draw();
      });

      // 设置下拉列表选中项为'All'
      select.val('');
    }
  });
});