JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.jquery.com/mobile/1.4.0-beta.1/jquery.mobile-1.4.0-beta.1.min.js"></script>
<select id="ddl1">
  <option value="1">Text 1</option>
  <option value="2">Text 2</option>
  <option value="3">Text 3</option>
  <option value="4">Text 4</option>
</select> 

<select id="ddl2">
  <option value="1">Text 1</option>
  <option value="2">Text 2</option>
  <option value="3">Text 3</option>
  <option value="4">Text 4</option>
</select>

JavaScript

$("#ddl1").change(function() {
	var code = $(this).val();
    $("#ddl2").val(code);
});