const ws_url = new URL('ws', window.location.href);
ws_url.protocol = ws_url.protocol.replace('http', 'ws');
const ws = new WebSocket(ws_url.href);

ws.onmessage = function(event) {
    const msg = JSON.parse(event.data);

    console.log(msg);

    if (msg.hasOwnProperty('session')) {
        document.getElementById('current_session').innerText = msg.session;
    }
};