JSFiddle - React, Tailwind, and code Playground
HTML
<select>
<optgroup label="Other" id="custom">
<option value="mentorCustom">Search For Agent</option>
</optgroup>
</select>
<button>Add Option</button>
JavaScript
(function () {
"use strict";
var custom = document.querySelector( "#custom" );
var button = $("button");
button.on("click", addOption);
function addOption () {
$("<option>").text( +new Date ).appendTo( custom );
}
}());