JSFiddle - React, Tailwind, and code Playground

HTML

<table id="tableid" border=1 width="200px">
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
<tr><td>1</td><td>2</td></tr>
</table>

JavaScript

var mytable = document.getElementById('tableid');
var myrows = mytable.getElementsByTagName("tr");
var lastrow = myrows[myrows.length -1];
var mycells = lastrow.getElementsByTagName("td");
var lastcell = mycells[mycells.length -1];
lastcell.style.color = "red";