From old-style to Single Page Applications

Web applications are the best known application types involving JavaScript. Since its appearance, JavaScript and web browsers have established a lasting symbiosis that still holds, although with slightly different roles than in the past. In this context, in fact, we have seen a growing responsibility of JavaScript whose evolution, together with the evolution of HTML, has led us to create applications with an interaction model and an architecture very similar to desktop applications.

Old-style web applications

The traditional architecture of the early web applications consisted (and still consists) of a set of HTML pages, representing the user interface, with JavaScript scripts whose main task was managing the user interaction and rendering some graphic effects. As a part of this architecture, the transition from one screen to the next one implied a request to the server and a whole page loading, with obvious latency, especially if the page was very...