JSON返回show function detail（）{[native code]}

Question

我在user.php页面中使用了一个轮询脚本，它使用长轮询JS从upsidenew.php页面获取新事件（if）。

现在我的问题，为什么我的脚本显示返回结果：function detail（）{[native code]}

请参阅下面的代码;这是我完整的民意调查代码。

我的Sql表名称：updateside

id - work_id - parent_id - from_id - to_id - sub - detail - img - created
..........................................................................

AI - work_id, parent_id etc. all data collect by user post form  

在我的upsidenew.php页面中：

$parent = $row['parent_id']; // collect from above query
date_default_timezone_set('Asia/Dhaka');
$timestamp = date("M j, y; g:i a", time() - 2592000);

$u = mysqli_query($dbh,"SELECT * FROM updateside WHERE `parent_id`='".$parent."' AND `created` > '".$timestamp."' ORDER BY created DESC") or die(mysqli_error($dbh));
while ($row = mysqli_fetch_array($u)) {
$result['from_id'] = $row['from_id'];
$result['parent_id'] = $row['parent_id'];
$result['detail'] = $row['detail'];
.....
...
header('Content-Type: application/json');
echo json_encode($result);
exit;
}

在user.php页面上我的JavaScript：

    function waitForMsg(){
    $.ajax({
        type: "GET",
        url: "upsidenew.php",
        async: true, 
        cache: false, 
        timeout:50000, 
        datatype: 'json',
success: function(data){ 
        if(data) {
        $("#updatetime").html('<div class="upbox1" id=" '+ parent_id + '"> ' + data.detail + '</div>');
        }
setTimeout(
                waitForMsg, /* Request next message */
                1000 /* ..after 1 seconds */
            );
        },
        error: function(XMLHttpRequest, textStatus, errorThrown){
            addmsg("error", textStatus + " (" + errorThrown + ")");
            setTimeout(
                waitForMsg, /* Try again after.. */
                15000); /* milliseconds (15seconds) */
        }
    });
}

$(document).ready(function () {
            waitForMsg(); /* Start the inital request */
});