require 'facebook/src/facebook.php';
$facebook = new Facebook(array(
    'appId' => 'xxxxxxx',
    'secret' => 'xxxxxxxx',
    'cookie' => true
));
$user = $facebook->getUser();

if ($user) {
    try {
        // Proceed knowing you have a logged in user who's authenticated.
        $user_profile = $facebook->api('/me');
    } catch (FacebookApiException $e) {
        //echo '<pre>'.htmlspecialchars(print_r($e, true)).'</pre>';
        $user = null;
    }

}

var_dump($user_profile);exit;