VTI / SockJS-0.05 / t-vendor / html / smoke-latency.html 
<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta charset="UTF-8" />

  <link href="data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQEAYAAABPYyMiAAAABmJLR0T///////8JWPfcAAAACXBIWXMAAABIAAAASABGyWs+AAAAF0lEQVRIx2NgGAWjYBSMglEwCkbBSAcACBAAAeaR9cIAAAAASUVORK5CYII=" rel="icon" type="image/x-icon" />

  <script type="text/javascript" src="lib/sockjs.js"></script>
  <script type="text/javascript" src="static/jquery.min.js"></script>

  <script type="text/javascript" src="config.js"></script>
</head>
<body>
<form>
  <select id="transport">
  <option value="">- any - </option>
  <option value="websocket">websocket</option>
  <option value="xdr-streaming">xdr-streaming</option>
  <option value="xhr-streaming">xhr-streaming</option>
  <option value="iframe-eventsource">iframe-eventsource</option>
  <option value="iframe-htmlfile">iframe-htmlfile</option>
  <option value="xdr-polling">xdr-polling</option>
  <option value="xhr-polling">xhr-polling</option>
  <option value="iframe-xhr-polling">iframe-xhr-polling</option>
  <option value="jsonp-polling">jsonp-polling</option>
  </select>
  <input type="button" value="Connect" id="connect">
  <input type="button" value="Disconnect" id="disconnect" disabled="yes">
</form>

  Latency: <code id="latency"></code><br>
  <code id="logs" style="height:200px; overflow:auto; display: block; border: 1px gray solid;">
  </code>

<script>
    function log(a) {
            if ('console' in window && 'log' in window.console) {
                console.log(a);
            }
            $('#logs').append($("<code>").text(a));
            $('#logs').append($("<br>"));
            $('#logs').scrollTop($('#logs').scrollTop()+10000);
      }

    var sjs;
    function onopen() {
            log('connected ' + sjs.protocol);
            send();
    };
    function onclose(e) {
            log('disconnected ' + e);
            $('#connect').each(function(_,e){e.disabled='';});
            $('#disconnect').attr('disabled', true);
    };
    function send() {
        sjs.send(JSON.stringify({t: (new Date()).getTime()}));
    };
    var i = 0;
    function xonmessage(e) {
            var msg = JSON.parse(e.data);
            var td = (new Date()).getTime() - msg.t;
            $('#latency').text(''+i +'  ' + td + ' ms');
            i += 1;
            send();
    };

    $('#connect').click(function() {
        $('#connect').attr('disabled', true);
        $('#disconnect').each(function(_,e){e.disabled='';});
        var protocol = $('#transport').val() || undefined;
        log('[connecting] ' + protocol);
        options = jQuery.extend({}, client_opts.sockjs_opts)
        options.protocols_whitelist = typeof protocol === 'string' ?
                                                        [protocol] : protocol;
        sjs = new SockJS(client_opts.url + '/echo', null, options);
        sjs.onopen = onopen
        sjs.onclose = onclose;
        sjs.onmessage = xonmessage;
    });
    $('#disconnect').click(function() {
        $('#disconnect').attr('disabled', true);
        log('[disconnecting]');
        sjs.close();
    });
</script>
</body>
</html>