AJAX is a complex phenomenon that means different things to different people. Computer users
appreciate that their favorite websites are now friendlier and feel more responsive. Web
developers learn new skills that empower them to create sleek web applications with little effort.
Indeed, everything sounds good about AJAX!
At its roots, AJAX is a mix of technologies that lets you get rid of the evil page reload, which
represents the dead time when navigating from one page to another. Eliminating page reloads is
just one step away from enabling more complex features into websites, such as real-time data
validation, drag and drop, and other tasks that weren't traditionally associated with web
applications. Although the AJAX ingredients are mature (the XMLHttpRequest object, which is
the heart of AJAX, was created by Microsoft in 1999), their new role in the new wave of web
trends is very young, and we'll witness a number of changes before these technologies will be
properly used to the best benefit of the end users. At the time of writing this book, the "AJAX"
name is about just one year old.
AJAX isn't, of course, the answer to all the Web's problems, as the current hype around it may
suggest. As with any other technology, AJAX can be overused, or used the wrong way. AJAX
also comes with problems of its own: you need to fight with browser inconsistencies,
AJAX-specific pages don't work on browsers without JavaScript, they can't be easily
bookmarked by users, and search engines don't always know how to parse them. Also, not
everyone likes AJAX. While some are developing enterprise architectures using JavaScript,
others prefer not to use it at all. When the hype is over, most will probably agree that the middle
way is the wisest way to go for most scenarios.