websocket-terminal-cpp-server/frontend.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <script src="https://cdn.jsdelivr.net/npm/xterm@4.2.0/lib/xterm.min.js"></script>
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/xterm@4.2.0/css/xterm.min.css">
</head>
<body>
  <div class="terminal" style="width: min-content; font-size: 12px;"></div>
  <script>
    const socket_url = `${location.protocol === 'http:' ? 'ws:' : 'wss:'}//${location.host}${location.pathname}`
    const socket = new WebSocket(socket_url);

    socket.onopen =() => {
      window.term = new Terminal({
        cols: 80,
        rows: 24,
        fontFamily: 'SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace',
      });

      term.onData(data => socket.send(data));

      term.open(document.querySelector('.terminal'));

      socket.onmessage = (message) => {
        term.write(message.data);
      }
    };

  </script>
</body>
</html>