Professional Ruby on Rails™

Chapter 8. Rails-Driven Javascript

As it happens, I spent a significant part of the years 1999 and 2000 arguing against putting large amounts of JavaScript in the client sites I was developing. My arguments were that the tool support was weak, so a lot of developer effort was involved, it was hard to debug, and almost anything complex was guaranteed to break on one or the other of the two major browsers. Furthermore, the range of things people were doing with JavaScript at the time wasn't so compelling that it seemed to require throwing it into our sites.

That was a long time ago — the iPod didn't even exist yet — and times have changed. JavaScript is now a critical part of many of the Web's most popular sites. Much of this has been driven by a simple functionality enhancement that did not exist in 1999: the capability to call a server asynchronously from within JavaScript. That simple capability, from the XmlHttpRequest object that is now a standard part of JavaScript, has enabled a much richer and more interactive Web experience, ranging from special effects, to Ta-Da Lists, to scrolling Google Maps, to rich online document editing. Eventually, the new interaction structure was isolated and named Ajax, which is a pseudo-acronym for Asynchronous JavaScript And XML, and the name has stuck.

Rails was one of the first toolkits to make dealing with Ajax easy to do without having to know a great deal of JavaScript. Since the initial release of Rails, the addition of RJS scripts has ...