public static function plain_page($title, $content, $meta = '') {
        if (function_exists('get_string') && function_exists('get_html_lang')) {
            $htmllang = get_html_lang();
        } else {
            $htmllang = '';
        }

        $footer = '';
        if (MDL_PERF_TEST) {
            $perfinfo = get_performance_info();
            $footer = '<footer>' . $perfinfo['html'] . '</footer>';
        }

        return '<!DOCTYPE html>
<html ' . $htmllang . '>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
'.$meta.'
<title>' . $title . '</title>
</head><body>' . $content . $footer . '</body></html>';
    }