JSFiddle - React, Tailwind, and code Playground
HTML
<input type="button"
onclick="$('<tr><td >df</td></tr>').appendTo('#CT');" value="fff">
<table>
<tr id="CT4"><td></td></tr>
<tr id="CT5"><td>5</td></tr>
<tr id="CT6"><td>6</td></tr>
</table>
JavaScript
$('#CT5').after('<tr><td>9</td></tr>');