Web development has changed dramatically over the past year with the implementation of Asynchronous JavaScript + XML, also known as Ajax.
Ajax has become a fixture in technology lexicon. It is derived from Microsoft’s work on remote scripting, a technology that did not catch on in the days when dialup Internet access was the norm for users outside the workplace.
That changed near the end of winter in 2005. On February 18th of that year, Adaptive Path’s Jesse James Garrett posted an essay about the use of Ajax in web development. It proved to be a turning point, as the technology has become widely used, almost to the point where hardcore web users find themselves disappointed when a web application does not use it in a likely place.
In discussing Ajax (a term created at Adaptive Path), Garrett noted that it isn’t a technology in itself. Instead, it combines several technologies:
• standards-based presentation using XHTML and CSS;
• dynamic display and interaction using the Document Object Model;
• data interchange and manipulation using XML and XSLT;
• asynchronous data retrieval using XMLHttpRequest;
• and JavaScript binding everything together.
Most people see Ajax purely in its client-side glory. A web page like Yahoo! News uses it extensively. It’s probably fair to say that Yahoo’s developers have driven Ajax into public awareness with their work more than Google or anyone else.
Behind the scenes, an Ajax engine sits between the front-end web browser and the back-end server. The user sees a page, while the engine makes JavaScript calls for data to the back-end.
The net effect has the application changing information displayed on a web page without performing a full refresh of the browser window and waiting for everything to reload. Ajax gives these applications a look and feel resembling that of rich desktop software.
“The Ajax engine allows the user’s interaction with the application to happen asynchronously – independent of communication with the server,” Garrett wrote. “So the user is never staring at a blank browser window and an hourglass icon, waiting around for the server to do something.”
Some developers will see Ajax doing what Adobe’s Flash technology can do; they may even prefer Flash to Ajax. Garrett noted that as Ajax matures, there would be solutions where it is best suited, and ones where Flash makes the most sense.
It’s all up to the developer. A good resource to see the growing field of Ajax-powered applications may be found at TechCrunch, which features up-and-coming websites where many use Ajax to deliver a better user experience.
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David Utter is a staff writer for Murdok covering technology and business.
