popup.html

  <!DOCTYPE html>
  <html>
    <head>
      <style>
        button {
          height: 30px;
          width: 180px;
          outline: none;
        }
      </style>
	  <script src="popup.js"></script>
    </head>
    <body>
      <div id="dont_check">
        <button id="delete">Don't browse periodically</button>
        <hr>
      </div>
      <div id="interval_list">
      </div>
      <hr>
      <button id="options">Open detailed options</button>
    </body>
  </html>