JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/ui/1.11.4/jquery-ui.min.js"></script>
<p>Date: <input type="text" id="datepicker" /></p>

JavaScript

$('#datepicker').datepicker({
    onSelect: function (dateText, inst) {
          var date = $(this).datepicker('getDate');
          alert($.datepicker.formatDate('DD', date));
    }
});