JQuery ajax - weird answer

Good day! Help to overcome the problem with ajax. There is such a function

function ajax_message_delete(id, zadanie_id) { $.ajax({ url: "/ajax_script/messages_window.php", type: "POST", data: 'action=delete_message&id=' + id + '&zadanie_id=' + zadanie_id, success: function (data) { if (data) { $('.infrsend').html(data); $('#center_box').slimScroll({ height:150, start : 'bottom' }) ; } } }); 

}

After processing, a strange addition to the result is displayed, the screen by reference.

Processing in php (and it doesn't matter what happens with the response from the server side, you can just send "1"):

  if ($action == 'delete_message' && $id > 0 && $zadanie_id > 0) { //если админ if($moderator['status'] == 'admin' || $moderator['funct'][13] == 1) { //q("delete from `users_messages` where `id` = '$id'"); $messages = load_messages_window(0, $zadanie_id, 1); } //* //если не админ else { //узнаем с кем мы общались $q = q("select `user_to` from `users_messages` where `user_form` = '" . $_SESSION['user'][0] . "' and `id` = '$id'"); $user_to = mysql_fetch_row($q); //* q("delete from `users_messages` where `user_form` = '" . $_SESSION['user'][0] . "' and `id` = '$id'"); $messages = load_messages_window($user_to[0], $zadanie_id); } //* echo '<div class="center_box" id="center_box">' . $messages . '</div>'; }