下拉刷新异常

把页面往上拖动后，然后往下拉，页面还没有到达顶端就开始刷新

<div id="content" class="mui-content mui-scroll-wrapper" >  
  <div class="mui-scroll scroll-wrap" id="scroll">  

    <ul class="mui-table-view mui-table-view-chevron">                
    </ul>  
  </div>  
</div>  

<script>  
  mui.init({  
            pullRefresh:{  
                container:'#content',  
                down:{  
                    contentrefresh: '正在加载...',  
                    contentover: '释放立即刷新',  
                    callback: pulldownRefresh  
                }  
            }  
        });  
        function pulldownRefresh(){  
            setTimeout(function(){            
                mui('#content').pullRefresh().endPulldownToRefresh();  
            },5000);  

	

  

    }  
</script>