<html>
  <head>
  <script src="http://code.jquery.com/jquery-1.11.2.min.js"></script>
  <script src="http://code.jquery.com/jquery-migrate-1.2.1.min.js"></script>
  <script src="popup.js"></script>
  </head>

  <body>
    <form>
      <input type="number" class="duration" min='1' max='30'>
    </form>
    <button type="button" class="duration-button">Get Time</button>
    <button class="start-pairing" type="button">Start Pairing</button>
    <button class="pause-pairing" type="button">Pause Pairing</button>
    <button class="exit-pairing" type="button">Exit Pairing</button>
    <div class='countdown'></div>
  </body>
</html>
<html>
  <head>
  <script src="jquery-2.1.3.min.js"></script>

  <script src="popup.js"></script>
  </head>

  <body>
    <form>
      <input type="number" class="duration" min='1' max='30'>
    </form>
    <button type="button" class="duration-button">Get Time</button>
    <button class="start-pairing" type="button">Start Pairing</button>
    <button class="pause-pairing" type="button">Pause Pairing</button>
    <button class="exit-pairing" type="button">Exit Pairing</button>
    <div class='countdown'></div>
  </body>
</html>
Add Jquery to File Structure
Add Jquery to File Structure
