JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/ui/1.12.1/jquery-ui.min.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<select>
  <option value="one">One</option>
  <option value="two" selected>Two</option>
  <option value="three">Three</option>
</select>

<p></p>

JavaScript

var was = $('select').val();
$('select')
  .selectmenu()
  .on('selectmenuclose',function(event){
    var is = $('select').val();
    if(was == is) {
      $('p').append("<br>reselected "+is);
    }
    else {
      $('p').append("<br>changed to "+is);
    }
    was = is;
  });