jquery ajax 请求时间

$.ajax({
        url:'JsLongPollingMsgServlet',
        type:'post',
        dataType:'json',
        data:{"pageMsgNum":$("#pageMsgNum").val()},
        timeout:5000,
        success:function(data, textStatus){
            if(data && data.msgNum){
                                    //请求成功，刷新数据
                $("#msgNum").html(data.msgNum);
                                    //这个是用来和后台数据作对比判断是否发生了改变
                $("#pageMsgNum").val(data.msgNum);
            } 
            if(textStatus == "success"){
                                    //成功之后，再发送请求，递归调用
                getMsgNum();
            }
        },
        error:function(XMLHttpRequest, textStatus, errorThrown){
            if(textStatus == "timeout"){
                                    //有效时间内没有响应，请求超时，重新发请求
                getMsgNum();
            }else{
                                    // 其他的错误，如网络错误等
                getMsgNum();
            }
        }
    });

破罐子互摔