สอบถามการควบคุม การ Like ใน Facebook API หน่อยครับ (PHP & Javascript)

<?php
require '../src/facebook.php';
 
// Create our Application instance (replace this with your appId and secret).
$facebook = new Facebook(array(
  'appId' => 'APP_ID',
  'secret' => 'APP_SECRET',
));
 
$user = $facebook->getUser();
 
if ($user) {
  try {
    $likes = $facebook->api("/me/likes/PAGE_ID");
    if( !empty($likes['data']) )
        echo "I like!";
    else
        echo "not a fan!";
  } catch (FacebookApiException $e) {
    error_log($e);
    $user = null;
  }
}
 
if ($user) {
  $logoutUrl = $facebook->getLogoutUrl();
} else {
  $loginUrl = $facebook->getLoginUrl(array(
    'scope' => 'user_likes'
  ));
}
 
// rest of code here
?>