jquery实现轮询

 function showUnreadNews()
    {
        $(document).ready(function() {
            $.ajax({
                type: "POST",
                url: "unread_list.php",
                dataType: "json",
                success: function(data) {
                    //alert(msg);
                    $("#msg").append("data "+data);
                }
            });
        });
    }
    setInterval('showUnreadNews()',500);//轮询执行，500ms一次

 

getData($sql);
    if($result)
    {
        $arr = array('success' => "1", 'result' => $result);
        echo json_encode($arr);
        exit;
    }
    else{
         $arr = array('success' => "0", 'result' => "");
        echo json_encode($arr);
        exit();
    }
   
}