JSFiddle - React, Tailwind, and code Playground

by Sascha

HTML

<script src="https://code.jquery.com/jquery-3.4.1.slim.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
<input type="button" value="Add more panels" id="btnAddPanel">
<hr noshade>
<div class="container">
  <div class="form-row" id="panel-holder">

    <div class="col-xs-3">
      <div class="panel panel-default">
        <div class="panel-heading">
          <input type="hidden" id="invid1" name="invid" value="4111">
          Month 1
        </div>
        <div class="panel-body">
          ...
        </div>
      </div>
    </div>
  </div>
</div>

JavaScript

let month = 1;
$('#btnAddPanel').on('click', function() {
  month++;
  $('#panel-holder').append('<div class="col-xs-3"><div class="panel panel-default">' +
    '<div class="panel-heading"><input type="hidden" id="invid' + (month) + '" name="invid" value="4087">' + 'Month ' + (month) + '</div><div class="panel-body">...</div></div></div>');
});