JSFiddle - React, Tailwind, and code Playground

HTML

<select id=s>
  <option value=one>One</option>
  <option value=two>Two</option>
</select>

JavaScript

var elem = document.getElementById('s'), 
    $elem = $(elem);

$elem.change(function (event) {
	console.log(event.target.options.length)
});

console.log(elem)
$elem.change()

var o = new Option('three', 'Three')
elem.options[elem.options.length] = o;
console.log(elem)

$elem.change()