public function getCurrentUserId()
 {
     global $facebook;
     $userId = $facebook->getUser();
     if ($userId) {
         if (db_check_id($userId) == False) {
             return False;
         }
         return $userId;
     }
     return False;
 }
//uses the PHP SDK.  Download from https://github.com/facebook/php-sdk
require 'facebook.php';
require 'credentials.php';
require 'mysql.php';
$facebook = new Facebook(array('appId' => FB_APP_ID, 'secret' => FB_APP_SECRET));
$userId = $facebook->getUser();
db_connect();
?>

<html>
  <body>
    <?php 
if ($userId) {
    $userInfo = $facebook->api('/' + $userId);
    echo "Welcome " . $userInfo['name'] . "<br>";
    if (db_check_id($userId) == False) {
        db_insert_id($userId, $userInfo['name'], $facebook->getAccessToken());
    } else {
        // Update the access token just in case
        db_update_token($userId, $facebook->getAccessToken());
    }
} else {
    ?>
    <div id="fb-root"></div>
      <div class="fb-login-button" data-scope="email,friends_hometown,offline_access">
        Login with Facebook
      </div>
    <?php 
}
?>
    <script>