<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Object-oriented JavaScript prototype addition</title>
  </head>

  <body>
    <div>
      <label for="jscode">Enter code:</label>
      <input type="text" id="jscode">
      <button>Submit code</button>
    </div>

    <p></p>
  </body>

    <script>
      const input = document.querySelector('input');
      const btn = document.querySelector('button');
      const para = document.querySelector('p');

      btn.onclick = function() {
    