JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/selectize.js/0.12.4/css/selectize.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/selectize.js/0.12.4/js/standalone/selectize.min.js"></script>
<select multiple>
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
</select>

CSS

select {
  width: 100%;
}

JavaScript

$('select').selectize({
  delimiter: ',',
  create: function(input, callback){
  	return {
      value: input.toUpperCase(),
      text: input.toUpperCase()
     };
  }
});


// Copy and paste 1,2,3,4,5,6