JSFiddle - React, Tailwind, and code Playground

HTML

<table id="table1">
    <tr>
    <td>Value</td>
    <td><select onchange="myFunction(this);">
    <option value="1">1</option>
    <option value="2">2</option>
        </select>
    </td>
    </tr>
</table>

JavaScript

function myFunction(a)
{
    alert(a.parentNode.parentNode.inedx);
    a.parentNode.parentNode.style.backgroundColor = "yellow";
}