scope パラメータと redirect パラメータを含める必要があります。
$config = array();
$config['appId'] = 'xxx';
$config['secret'] = 'xxx';
$facebook = new Facebook($config);
if(isset($_GET['act']) && $_GET['act'] == "logout") {
$facebook->destroySession();
}
$user = $facebook->getUser();
echo $user;
if ($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>';
$user = null;
}
echo "<pre>";
print_r($user_profile);
echo "</pre>";
$logout = $facebook->getLogoutUrl();
//echo $logout;
echo "<a href='test.php?act=logout'>Logout</a>";
} else {
$login = $facebook->getLoginUrl(array("scope"=>"email","display"=>"popup","redirect_uri"=>"http://domain.com/test.php"));
echo "<a href='".$login."'>Login</a>";
}