jquery ajax双击div可直接修改div中的内容

<div title="【双击可直接修改】" class="changeSort" id="{$id}">{$sort}</div>

<script type="text/javascript">
//双击修改排序
 $('.changeSort').dblclick(function(){
  var url = "{:U('setSort')}";
  var td = $(this);
  var id = td.attr('id');
  var text = td.text();
  var txt = $("<input type='text' class='input-small' >").val(text);
  txt.blur(function(){
   // 失去焦点，保存值。于服务器交互自己再写,最好ajax
   var newText = $(this).val();
   $.ajax({
     url:url,
     type:'POST',
     data:{'tid':id,'sort':newText},
     dataType:'json',
     success:function(res){
      if(res.flag==1){
      layer.msg(res.msg);
      // 移除文本框,显示新值
      $(this).remove();
      td.text(newText);
      }else if(res.flag==3){
       layer.msg(res.msg);
       txt.val(newText);
      }
     }
    });
    
  });
  td.text("");
  td.append(txt);
 });
</script>

<?PHP
/**
  * ajax 设置排序值
  */
 public function setSort(){
  if(IS_POST){
   $tid = I('post.tid');
   $sort = I('post.sort');
   if(!is_numeric($sort)){
    $arr = array(
     'flag'=>3,
     'msg'=>'请输入数字',
     'link'=>'',
     'content'=>''
    );
    $this->ajaxReturn($arr);
   }
   $data = array(
    'id'=>$tid,
    'sort'=>$sort
   );
   $this->mod_sort = M('Sort');
   $res = $this->mod_sort->save($data);
   if($res){
    $arr = array(
     'flag'=>1,
     'msg'=>'排序值设置成功',
     'link'=>'',
     'content'=>''
    );
   }else{
    $arr = array(
     'flag'=>2,
     'msg'=>'排序值设置失败',
     'link'=>'',
     'content'=>''
    );
   }
  }else{
   $arr = array(
    'flag'=>0,
    'msg'=>'请求非法！',
    'link'=>'',
    'content'=>''
   );
  }
  $this->ajaxReturn($arr);
 }
?>