ROBN / Authen-U2F-0.003 / examples / demoserver / register.html.tt2 
<!DOCTYPE html>
<html>
<head>
   <title>U2F Demo</title>
   <script src='/u2f-api.js'></script>
</head>
<body>
  <p id='message'>waiting for device... </p>
  <script>
    var req = [% u2f.register_request %];
    u2f.register(location.origin, [ req.registerRequest ], req.registeredKeys, function (r) {
      if (r.errorCode) {
        document.getElementById('message').innerText += " error "+r.errorCode;
      }
      else {
        document.getElementById('message').innerText += "got it!";
        window.location = "/save_registration?clientData="+encodeURIComponent(r.clientData)+"&registrationData="+encodeURIComponent(r.registrationData);
      }
    });
  </script>
</body>
</html>