Chapter 9. Dynamic Interaction between Client and Server with Socket.IO

The original design model of the Web is similar to the way that mainframes worked in the 1970s. Both old-school dumb terminals, such as the IBM 3270, and web browsers follow a request-response paradigm. The user sends a request and the far-off computer sends a response screen. While web browsers can show more complex information than old-school dumb terminals, the interaction pattern in both cases is a back and forth of user requests, each resulting in a screen of data sent by the server screen after screen or, in the case of web browsers, page after page.

We are progressing rapidly. Web browsers with modern JavaScript engines can do so much more than the dumb terminals of yesteryear, or even the web browsers of just a couple years ago. One new technique is to keep a connection open with the server for continual data exchange between server and client, representing a change in the web application model; some call this...