jQuery基于排序功能实现上移、下移的方法

<tr id="{sh:$vo.id}">
  <td>
    <span onclick="up(this);" class="glyphicon glyphicon-arrow-up text-danger up" style="cursor: pointer;" title="上移" aria-hidden="true"></span>
    &nbsp;&nbsp;
    <span onclick="down(this);" class="glyphicon glyphicon-arrow-down text-danger down" style="cursor: pointer;" title="下移" aria-hidden="true"></span>
  </td>
  <td>
    <span title="{sh:$vo.user_id}">{sh:$vo.store_name}</span>
  </td>
  <td class="center"><a href="{sh:$vo.logo}" target="_blank"><img src="{sh:$vo.logo}" width='30px;'></td>
  <td class="center">{sh:$vo.category_name}</td>
  <td class="center edit">
    <a val="{sh:$vo.store_id}" onclick="view(this);" class="view btn btn-success" href="javascript:void(0);" title="查看">
      <i class="halflings-icon white zoom-in"></i>
    </a>
  </td>
</tr>

// 上移
function up(obj){
  var $tr = $(obj).parents("tr");
  if ($tr.index() != 0) {
    var current_id  = $tr.attr('id');
    var exchange_id  = $tr.prev("tr").attr('id');
    $.ajax({
      url: '{sh::U("Mall/ajax","todo=exchange_sort")}',
      type: 'POST',
      data: 'current_id='+current_id+'&exchange_id='+exchange_id,
      success:function(json) {
        if (json == 1) {
          $tr.fadeOut().fadeIn();
          $tr.prev().before($tr); 
          layer.msg('上移成功', {icon: 1});
        } else {
          layer.msg('上移失败', {icon: 2});
        }
      }
    });
  }
}
// 下移
function down(obj) {
  var len = $(".down").length;
  var $tr = $(obj).parents("tr");
    if ($tr.index() != len - 1) { 
      var current_id  = $tr.attr('id');
      var exchange_id  = $tr.next("tr").attr('id');
      $.ajax({
        url: '{sh::U("Mall/ajax","todo=exchange_sort")}',
        type: 'POST',
        data: 'current_id='+current_id+'&exchange_id='+exchange_id,
        success:function(json) {
          if (json == 1) {
            $tr.fadeOut().fadeIn();
            $tr.next().after($tr); 
            layer.msg('下移成功', {icon: 1});
          } else {
            layer.msg('下移失败', {icon: 2});
          }
        }
      });
  } 
}

case 'exchange_sort':
$mallShopModel = M('Mall_shop');
$current_id  = $this->_post('current_id','trim');
$exchange_id  = $this->_post('exchange_id','trim');
$current_sort = $mallShopModel->where(array('id'=>$exchange_id))->getField('sort');
$exchange_sort = $mallShopModel->where(array('id'=>$current_id))->getField('sort');
$cdata['id']  = $current_id;
$cdata['sort'] = $current_sort;
$cres     = $mallShopModel->save($cdata);
$edata['id']  = $exchange_id;
$edata['sort']  = $exchange_sort;
$eres     = $mallShopModel->save($edata);
if ($cres !== FALSE && $eres !== FALSE){
  exit('1');
} else {
  exit('2');
}