JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">
 
<div id="parent">
Date: <input type="text" class="datepicker"><input type="button" value="Add"  id="btn"> 
</div>

JavaScript

$(function() {
    $( ".datepicker" ).datepicker();
  });
    $(document).ready(function () {

        $("#btn").click(
            function () {
                AlertSave();
            }            
        );
    });

function AlertSave() {
      var textBox = document.createElement("input");
      textBox.setAttribute("class","datepicker");
    document.getElementById("parent").appendChild(textBox);


}