Ajax Design Patterns

Chapter 1. Introducing Ajax

BY NOW, YOU’VE PROBABLY USED AJAX ON SITES LIKE GOOGLE MAPS (HTTP://MAPS.GOOGLE.COM) Amazon’s A9 search engine (http://a9.com), and Flickr (http://flickr.com). Despite their different domains, all these web sites make heavy use of Ajax. The technology lets them take a great leap forth towards the richness of standard desktop applications, and in a manner which still respects the established conventions of the Web.

Ajax and the Usable Web

No longer are you forced to wait five seconds a web page to reload every time you click on something. Ajax applications change in real-time. They let you drag boxes around instead of clicking on arrows and typing in numbers. They keep page content fresh instead of forcing you to keep hitting Refresh. They show meaningful animations instead of verbose messages.

At the heart of all this is a growing emphasis on web usability.^[*] Perhaps you’ve heard the story of the dancing bear—everyone’s impressed with it even though its skills quite frankly wouldn’t get the bear into a dance academy;^[*] it makes an impression because it can dance and not because of how well it well dances. The Web felt like that at first. Suddenly you could read news from the other side of the world, find hints on some obscure game, purchase a rare book. All valuable activities, regardless of how easy or difficult to perform them. Usability? We don’t need no stinkin’ usability!

Here’s what happened: people discovered that any coder and his dog can build ...