cmd/web/client.html

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <script>
    window.addEventListener("load", function (evt) {
      var ws;

      ws = new WebSocket("ws://localhost:8081/bingo/play");
      ws.onopen = function (evt) {
        console.log("OPEN");
      }
      ws.onclose = function (evt) {
        console.log("CLOSE");
        ws = null;
      }
      ws.onmessage = function (evt) {
        console.log(evt.data);
      }
      ws.onerror = function (evt) {
        console.log("ERROR: " + evt.data);
      }
    });
  </script>
</head>

<body>
  <p>PRESS <b>F12</b> TO SEE LOGS</p>
</body>

</html>