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. That request-response paradigm is evident in the Node.js HTTP Server API, as shown in the following code:
http.createServer(function (request, response) {
... handle request
}).listen();
The paradigm couldn't be more explicit than this. The request and the response are right there.
It wasn't until JavaScript improved that we had a quite different paradigm. The new paradigm is interactive communication driven by browser-side JavaScript. This change in the web application model is called, by some, the real-time web. In some cases, websites keep an open...