public function xhtml()
    {
        $this->htmlattrs['xmlns'] = 'http://www.w3.org/1999/xhtml';

        echo '<?xml version="1.0" ?>'."\n";
        echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"';
        Core\Generator::lineBreak();
        Core\Config::set('tabs', '++');
        Core\Generator::tabs();
           echo '"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">';
           Core\Generator::lineBreak();
        Core\Config::set('tabs', '--');

        echo $this->getHtml();
        echo $this->getHead();
    }