This is truly the age of the browser interface. Internet Websites and Web applications increasingly offer rich, dynamic, browser-based user interfaces that deliver everything you expect from an installed desktop application. These applications deliver function and ease-of-use without requiring expensive desktop software installs.

The underlying technology for this browser UI approach has existed for a decade but the term AJAX was coined in 2005 by Jesse James Garrett of Adaptive Path. The core of this approach is the ability to make dynamic, asynchronous data requests of a Web server without having to reload the Web page or hit the refresh button. This approach enables Web developers to build rich UIs that run on every browser and across every popular platform.

In the last three years many JavaScript frameworks with AJAX support have become available from open source projects and commercial vendors. These include Prototype, script.aculous (which is built on top of Prototype), Dojo, Google Web Toolkit (GWT), DWR, TIBCO General Interface, and Yahoo UI.

These capabilities continue to evolve rapidly and Web developers now have a wide array of powerful UI tools they can use to build their Web applications.

The toolset for the QA staff responsible for testing and certifying AJAX applications hasn’t caught up yet with the capabilities being offered to Web developers. Currently most AJAX testing is being done manually.

Modern Web applications have n-tier architectures that communicate via messaging. A new generation of testing tools will provide recording of and visibility into the detail message events that affect the function of AJAX UIs.

For the first time, application testers need to understand the structure and semantics of the messages (down to the packet level) being exchanged to design tests for these applications.