when browser close session should be signout

I tried to session out when browser closes but it will not working.


In config file

1,$config['sess_expire_on_close'] = TRUE;


$config['sess_driver'] = 'files';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 0;
$config['sess_save_path'] = NULL;
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = FALSE;