protected function outputOpeningTag()
    {
        echo '<', htmlspecialchars($this->_tag);
        foreach ($this->_attributes as $name => $value) {
            echo ' ', htmlspecialchars($name), '="', htmlspecialchars($value), '"';
        }
        echo '>';
        if ($this->_tag == 'html' || $this->_tag == 'head' || $this->_tag == 'body') {
            echo "\n";
        }
    }