JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
 <select  name="shares" id="shares">
  <option value="500">500</option>
  <option value="1000">1000</option>
  <option value="1500">1500</option>
</select>
<h1 id="demo"></h1>

JavaScript

$("#demo").html($("#shares").val());
$("#shares").on('change',function(){
    var values = $(this).val();
     $("#demo").html(values);
    
    });