public static function writeHtmlTag($tag_name, $content = '', $attrs = array(), $intag_close = false)
    {
        $str = '<'.$tag_name.self::parseAttributes( $attrs );
        if (empty($content) && true===$intag_close) {
            $str .= self::$html_tag_closure;
        } else {
            $str .= '>'.(is_string($content) ? $content : '').'</'.$tag_name.'>';
        }
        return $str;
    }