JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<link rel="stylesheet" href=" https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js"></script>
<select id="tag" multiple class="js-example-basic-single" style="width:400px">
  <option value="A">A</option>
  <option value="B">B</option>
  <option value="C">C</option>
</select>
<button onclick="Notificate()">
Get
</button>

JavaScript

$(document).ready(function() {
    $("#tag").select2({
      tags: true
    });
});


function Notificate (){
	alert($("#tag").val());
}