public static function clean_page_url($name)
    {
        $name = str_replace(array(' '), '_', $name);

        $name = self::trim_extension_off($name);
        $name = self::trim_sort_number($name);

        if (preg_match('/^[\/]?index[\/]?/', $name)) {
            return '';
        }

        return strtolower($name);
    }