JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<form action="#" id="demoForm" class="demoForm">
  <select id="SelectEquipmentDropdown" onchange="myFunction()">
    <option value="1">1</option>
    <option value="2">2</option>
  </select>
</form>
<script>
function myFunction(){
var e = document.getElementById("SelectEquipmentDropdown");
var selectedEquipmentDropdown = e.options[e.selectedIndex].value;

alert(selectedEquipmentDropdown);
}
</script>