function get_cat() {
    let $t = $(this), catID = $t.val();
    let $next = $t.siblings('.subcat').filter(function() {
      return $t.index() < $(this).index();
    }).off('change').remove();
    if (catID != '') {
      $.get(location.href, { ajax: 1, subcat: catID }, res => $t.after(res));
    }
    return true;
  }