Node.js and socket.io don't work on Cloud9 IDE

Does anyone has experience to have Node.js and socket.io working on Cloud9 IDE?

The "Example (NodeJS with Socket.io)" (at https://c9.io/site/blog/2013/05/native-websockets-support/) doesn't work.

First, the server (https://c9.io/etlolap/webapp, /test.js) throws an error unless I fix as follow. I clicked Run button while test.js is on active tab.

var 
  socketIo = require('socket.io'),
  io = socketIo.listen(Number(process.env.PORT));
io.sockets.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
  console.log(data);
  });
});

Then, my client (https://c9.io/etlolap/webapp, /test.html) still cannot connect. I clicked Preview button while test.html is on active tab.

<!doctype html>
<html>
  <head>
    <script src="/socket.io/socket.io.js"></script>
    <script>
      var socket = io.connect('https://webapp-c9-etlolap.c9.io');
      socket.on('news', function (data) {
        console.log(data);
        socket.emit('my other event', { my: 'data' });
      });
    </script>
  </head>
  <body>
    Loading...
  </body>
</html>

and got error message below.

Failed to load resource: the server responded with a status of 404 --- (Not Found) https://c9.io/socket.io/socket.io.js

Uncaught ReferenceError: io is not defined --- test.html:6