static.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Gyro Client</title>
    <style>
    </style>
  </head>
  <body>
    <p>Version: 1</p>
    <p><label id="lblConnected"></label></p>
    <script>
      let bar = window.location.href;
      let wsAddress = `ws://${bar.match(/^https?:\/\/([^:]+).+$/)[1]}:1337`;
      console.log(wsAddress);
      var ws = new WebSocket(wsAddress);

      let scale = 960;

      ws.onopen = function(ws_evnt) {
        window.document.getElementById("lblConnected").textContent = "Connected";
        
        window.ondevicemotion = function(motion) {
          let data = {
            ts: Date.now(),
            gyro: {
              x: scale * motion.rotationRate.alpha,
              z: scale * motion.rotationRate.beta,
              y: -scale * motion.rotationRate.gamma,
            },
          }
          ws.send(JSON.stringify(data, function(key, val) {
            return val.toFixed ? Number(val.toFixed(20)) : val;
          }));
        };
      };
    </script>
  </body>
</html>