JSFiddle - React, Tailwind, and code Playground

HTML

<select id="productchoice">
   <option value="1">Option #1</option>
   <option value="2">Option #2</option>
  </select>

  <select id="productchoice2">
   <option value="1">Option #1</option>
   <option value="2">Option #2</option>
  </select>

JavaScript

$('#productchoice').change(function (){

        $('#productchoice2').val($(this).val());

});