websocketclient_demo.html

<!DOCTYPE html>
<html>
  <head>
      <meta charset="utf-8">
      <title>RemoteControl demo</title>
      <style type="text/css">
          .buttons {
              font-size: 1em;
              display: flex;
              justify-content: center;
          }
          .button {
              padding: 2rem;
              border: medium solid;
              min-height: 1em;
              min-width: 1em;
              cursor: pointer;
              user-select: none;
          }
      </style>
  </head>
  <body>
    <div class="buttons">
      <div class="play button">Play</div>
      <div class="pause button">Pause</div>
    </div>
    <script>
      var websocket = new WebSocket("ws://localhost:8081/");

      var play = document.querySelector('.play')
      var pause = document.querySelector('.pause')

      play.onclick = function (event) {
        websocket.send(JSON.stringify({button: 'press_play'}));
      }
      pause.onclick = function (event) {
        websocket.send(JSON.stringify({button: 'press_pause'}));
      }
    </script>
  </body>
</html>