<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Function library example</title>
  <style>
    input {
      font-size: 2em;
      margin: 10px 1px 0;
    }
  </style>
</head>
<body>

  <input class="numberInput" type="text">
  <p></p>

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

  </script>
</body>
</html>
