public function getExampleHtml($html = null)
    {
        if ($html === null) {
            if ($this->getMarkup() === null) {
                return '';
            }
            $html = $this->getMarkup();
        }

        if ($this->isExtender()) {
            $html = str_replace('$modifierClass', '', $html);

            // Use a positive lookbehind and lookahead to ensure we don't
            // replace anything more than just the targeted class name
            // for example an element name that is the same as the extended
            // class name (e.g. button)
            $pattern = sprintf('/(?<="| )%s(?="| )/', $this->getExtendedClassName());
            $html = preg_replace(
                $pattern,
                $this->getClassName(),
                $html
            );
        }

        $html = str_replace('$modifierClass', $this->getClassName(), $html);

        return $html;
    }