Evolution of the web application

When you type a URL, such as www.example.com, into your browser, what actually happens? First, the browser would send a request to one of Example Corp's servers, which retrieves the resource requested (for example, an HTML file), and sends it back to the client:

The browser then parses the HTML, retrieves all the files the web page depends on, such as CSS, JavaScript, and media files, and renders it onto the page.

This scheme is known as the client-server model. In this model, most of the processing is handled server-side; the client's role is limited to simple and superficial uses, such as rendering the page, animating menus and image carousels, and providing event-based interactivity.

This model was popular in the 1990s and 2000s, when web browsers were not very powerful. Creating entire applications with JavaScript on the client side was unheard of, and those that had that requirement resorted to Java applets and Adobe Flash (and, to a certain extent, Microsoft Silverlight). However, over time, the computing power of personal devices, such as desktop computers, laptops, and smartphones increased dramatically, and this allowed browsers to handle more elaborate operations.