1.1. Rich Internet Applications

The Internet has changed a lot since its initial creation. It started with simple text-based communication and has built on its past to create ever more powerful means of communicating. In today's World Wide Web, you can create interactive multimedia presentations and powerful applications. Although these applications are powerful, they aren't without their drawbacks. Most are incredibly clumsy when compared to their native application counterparts (Hotmail versus Outlook Express, for instance), and many more have massive usability problems. However, problems or not, the Weband especially Web applicationsis one of the fastest growing and most important fields of software development.

Internet applications bring huge benefits to the table when compared to a normal application. They are highly accessible, require no installation, can be upgraded at any time, and offer access to large amounts of data without complex networks. These advantages allow for a shorter time to market, as well as lower development and support costs, when compared to a native application. Even though Internet applications usually have poorer usability due to their simpler, less interactive interfaces and slow update times, they are replacing native applications everywhere you look.

A Rich Internet Application (RIA) is an Internet application that attempts to bridge the usability gap between native applications and normal Internet ones. It contains more code on the browser, which offers higher levels of interactivity and an experience similar to native applications. With RIAs, it's possible to use many technologies, such as Flash, Java, and ActiveX, but the most important one is JavaScript. Because JavaScript is provided directly by the browser instead of being an add-on like the other technologies, you can get the most benefit from the least amount of work.

One of the driving technologies behind RIA in the JavaScript language is a technology called AJAX. AJAX offers the ability to communicate with your Web server outside of the normal load flow.