Once you push the "start listening" button your browser will open a request with my server, who will wait a random number of seconds (between 0 and 30) before returning a response. Your browser will then update it's log of the events and immediately open another request with my server. This demonstrates that the client and server are able to communicate on demand, as would be required to pass messages back and forth between client and server in a IM/chat program.

When you push the button the first time be patient because it could be up to 120 seconds before the server sends you the first message. Your connection is still alive, your client is just waiting on a message from the server, just like it would be if you were waiting for your counterpart in a conversation to type and send a message to you.