msgTest.html

<!DOCTYPE HTML>
<html>

<head>
    <meta charset="UTF-8">
    <title>MUSEControl msgTest</title>
</head>

<body>
    Messages<br>
    <pre id="jsonArea">
    </pre>
    <script src="js/libs/jquery-3.1.0.min.js"></script>
    <script src="js/libs/sprintf.js"></script>
    <script src="js/libs/socket.io-1.4.5.js"></script>
    <script src="js/libs/dat.gui.js"></script>
    <script src="js/CanvasTool.js"></script>
    <script src="js/util.js"></script>
    <script src="js/MUSEControl.js"></script>
    <script>
        var muse = null;
        $(document).ready(function () {
            muse = new MUSEControl();
            muse.sendMessage({type: 'joined'});
            muse.setMessageHandler(msg => {
                console.log("show msg", msg);
                var str = JSON.stringify(msg, null, 3);
                console.log("json str", str);
                $("#jsonArea").html(str);
            })
        });

    </script>
</body>