A Sneak Peek into AJAX

Ever since the first Web application was written, developers have attempted to create dynamic user interfaces that offer an interactive experience, much like desktop applications. Traditional Web applications feel clumsy and unresponsive because every update to the interface involves a full round-trip to the server and back. In this article, we will see how AJAX, a recent Web development technique, tackles this problem.

AJAX, an acronym for Asynchronous JavaScript and XML, takes advantage of your browser’s built-in abilities to handle standards-based presentation, dynamic display and interaction, data interchange and manipulation, and asynchronous data retrieval. With AJAX, your Web application’s interface is freed up from lock-step communication with the server. AJAX applications do not need to refresh the entire page to update information on it. Instead, only relevant parts of the page are updated, giving users immediate feedback on their actions. This allows users to continually see what they are working on and react to any changes, errors or updates.

Why AJAX is popular

Several factors have lead to an upsurge in AJAX’s popularity. First, many high profile companies like Google have created impressive applications using this technology — think Gmail, Google Maps and Google Calendar. These applications have proved that AJAX can be used for real-world solutions in the enterprise, not just inside labs. Second, because AJAX applications are built on current Web standards, Web developers already familiar with these standards can build AJAX applications with relative ease. Finally, many easy-to-use, well-documented building blocks (i.e., toolkits, libraries) are available on the Web. Developers can save time by integrating these with their applications, instead of writing code from scratch.

Diving into AJAX

Before you start developing new AJAX applications or migrating existing Web applications, a well-rounded understanding of AJAX technology and current toolkits is essential. Resources on the Web, dedicated to AJAX, are popping up every day. Apart from your standard Google search for the term ‘ajax’, two websites, Ajaxian and AJAX Matters really stand out. Both sites provide a wealth of articles, code samples and documentation, written by industry experts and developers. Deciding to integrate one of the many available AJAX toolkits can help you make the best of your AJAX development experience. The questions to consider before making your decision are:

• What are the toolkit’s strengths (i.e., fancy UI effects, ease of customization)?
• Is it easy to learn?
• Is it well documented?
• How does it perform?
• Is the code maintainable and easy to debug?
• Does it only integrate with specific technologies?
• What do current users have to say about it?
• What kind of license does it use (i.e., GPL, BSD)?

Looking ahead

AJAX changes the way we think about Web applications. For developers, AJAX encourages modularity — functionality handled by a hefty chunk of code can be split across several lightweight components that are easier to test and maintain. For users, AJAX promises to fuse the interactivity of desktop applications with the utility of the Web. The future looks bright for AJAX, given that large companies like Google, Yahoo!, IBM and Sun are committing significant developer resources to it.