demo.html

<!DOCTYPE html>
<html lang="de">
  <head>
    <meta charset="UTF-8" />
    <meta
      name="viewport"
      content="width=device-width, height=device-height, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"
    />
    <title>joke.town</title>
    <link rel="stylesheet" href="/assets/demo.css" />
  </head>
  <body>
    <div class="screen">
      <iframe src="/screen" height="1680" width="1050" frameborder="0"></iframe>
      <button class="down"></button>
      <button class="up"></button>
    </div>

    <div class="preload up"></div>
    <div class="preload down"></div>

    <script>
      const IOPORT = "{{IOPORT}}";
    </script>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.2.0/socket.io.js"></script>
    <script src="/assets/demo.js"></script>
  </body>
</html>