Hello friends i'm trying this method for get fb access token, but this is not working....
Return empty value 
define('FACEBOOK_APP_ID', 'xxxxxxxxxxxxxxxxxxxxxxxx');
define('FACEBOOK_SECRET', 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx');
function get_facebook_cookie($app_id, $app_secret) {
$args = array();
parse_str(trim($_COOKIE['fbs_' . $app_id], '\\"'), $args);
ksort($args);
$payload = '';
foreach ($args as $key => $value) {
if ($key != 'sig') {
$payload .= $key . '=' . $value;
}
}
if (md5($payload . $app_secret) != $args['sig']) {
return null;
}
return $args;
}
$cookie = get_facebook_cookie(FACEBOOK_APP_ID, FACEBOOK_SECRET);
echo $cookie['access_token'];