If you explore the leafletjs quickstart guide, specifically in the section labeled "Working with popups", try clicking on the blue marker displayed on the map. A popup will appear with the simple text "hello". But wouldn't it be interesting to have the popup show a table instead of just text? Imagine a basic 1x2 HTML table like this:
<table>
<tr>
<td>Cell 1</td>
<td>Cell 2</td>
</tr>
</table>