when new comment added database javascript must send notification [duplicate]

hello everyone im trying to when new comment added to the database , javascript will send notification and here is my code for ajax.php

    <?php

require_once "config.php";


$id = $_GET['id'];
$q = $_GET['q'];


$totalComments = 0;
$count = $db->count('comments', [
    "id[<]" => $id,
    'OR' => [
        "name[~]" => $q,
        "comment[~]" => $q,
    ],
]);
$totalComments += $count;

// Check if there are new comments
if ($totalComments!== $count) {
    
    // Instead, return a flag to indicate new comments
    $newComments = true;
} else {
    $newComments = false;
}

$result = getComment2($db, $id, $q?? '');


echo json_encode([
    "count" => $count,
    "data" => $count > 0? array_values($result) : null,
    "newComments" => $newComments, // Add a flag to indicate new comments
]);

and also here its my notification.js file

window.addEventListener('load', () => {
    if (!window.Notification) return;
  
    Notification.requestPermission().then(permission => {
      if (permission === 'granted') {
        // Listen for new comments flag from PHP script
        document.addEventListener('ajaxComplete', event => {
          const xhr = event.detail.xhr;
          const response = JSON.parse(xhr.responseText);
          if (response.newComments) {
            sendNotification();
          }
        });
      }
    });
  });
  
  const sendNotification = () => {
    let notification = new Notification('Yeni yorum', {
      body: 'Yeni yorum yapıldı. ',
      icon: '#icon yolu',
      title: 'Çiçek sepeti yorum'
    });
  };

when i try add new comment, nothing happens can someone help me ?