JSFiddle - React, Tailwind, and code Playground

HTML

<table border="0" cellpadding="0" cellspacing="5" style="width: 600px;">
<tbody>
<tr>
<td width="200px">Overskrift 1</td>
<td width="200px">Overskrift 2</td>
<td width="200px">Overskrift 3</td>
</tr>
    <tr class="clickable">
        <td colspan="3">Klik her for at gemme</td>
    </tr>
<tr>
<td style="vertical-align: top; width: 200px;">Help 1</td>
<td style="vertical-align: top; width: 200px;">Help 2</td>
<td style="vertical-align: top; width: 200px;">Help 3</td>
</tr>
</tbody>
</table>

JavaScript

$(".clickable").click(function() {

    $(this).next().toggle();
    
});