<?php
require_once 'openid.php';
    $openid = new LightOpenID("xxx.de");

    $openid->identity = 'https://www.google.com/accounts/o8/id';
    $openid->required = array(
                'namePerson/first',
  '             namePerson/last',
                'contact/email',
            );
    $openid->returnUrl = 'http://xxx/anmelden_google.php';
    $open_url = $openid->authUrl();
    ?>
<a href="<?php echo $open_url ?>">Login with Google</a>