JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<script src="https://ajax.aspnetcdn.com/ajax/jquery.validate/1.15.0/jquery.validate.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.css">
<select id="select" multiple="true">
  <option value="1">One</option>
  <option value="2">Two</option>
</select>

JavaScript

$( document ).ready(function() {
	var obj = [];
	$('#select').click(function(){
  	obj.push($(this).val());
    
    alert(obj);
  });
});