<details role="group">
<summary role="button" aria-expanded="false">Course schedule</summary>
<table>
<tr>
<th>Start date</th>
<th>End date</th>
<th>Duration</th>
</tr>
</table>
</details>
Source: http://www.creativebloq.com/html5/5-html5-and-aria-design-patterns-7133753