Five years ago, if you didn't know XML, you were out of the loop. Eighteen months ago, Ruby came into the limelight and programmers who didn't know Ruby were not in the know. Today, if you want to get into the latest technology rage, Ajax is it. AJAX is far more than just a fad; it is a powerful approach to building Web sites with a much smaller learning curve than being trained on an entire new language. Ajax has pros and cons but overall there are a variety of things AJAX can be used for that could previously not be done. DHTML allows users to make browser based applications look and behave like desktop applications, and the AJAX component all but eliminates screen transitions.