public static function html($message, $data = null)
    {
        if (!static::$on) {
            return;
        }

        echo "<hr>";
        echo "<i>";
            static::indent();
            echo "<b>" . static::getTime() . " - " . $message . "</b>";
            if (is_array($data)) {
                Html::print_r($data);
            } elseif ($data) {
                static::indent();
                echo "&nbsp;&nbsp;&nbsp;&nbsp;" . $data . "<br>";
            }
        echo "</i>";
    }