Summary: Introducing Ajax
Introducing Ajax
A little more than a year ago, an article by Jesse James Garrett was published describing an advanced web development technique that, even though individual components of it have existed for years, few web developers had ever stumbled across. I can guess the reason for this lack of knowledge; basically, in the last few years, the need to produce measurable results has gotten in the way of the need to practice our craft. Or, as a former manager of mine would say, it’s “that mad scientist stuff,” except, as I recall, he used another word in place of stuff. Unfortunately, nine times out of ten, the need to produce measurable results gets in the way of “that mad scientist stuff.”
However, it’s the tenth time that’s important. The article didn’t stop at just describing the technique; it went on to say that Google used the very same technique. Invoking that single name, Google, was enough to change a point of view. Quicker than you could say, “Igor, the kites!” the phrase “that mad scientist stuff” morphed into “Why aren’t we doing it this way?” The reason for this change of perception is that the name Google made this a technique that could produce measurable results. All it took was that single name, Google, to make using the XMLHttpRequest object so that the browser could communicate with the server without the page ever unloading and reloading into an acceptable practice.
This chapter introduces you to that practice, the practice of updating web pages with information from the server. Beyond the XMLHttpRequest object, which has been around for several years as a solution looking for a problem, there is nothing weird needed. Basically, it is how the individual pieces are put together. When they’re put together in one way, it is nothing more than a pile of parts; however, when put together in another way, the monster essentially rises from its slab.
Summary
This chapter (Introducing Ajax) started with a brief introduction to Ajax that included some of the origins and problems associated with using “mad scientist stuff,” such as the accusations of attempting to pass off a mock-up as an actual application and the inability to describe just how something works. Of course, some people still will think Corinthian helmets and hoplites at the very mention of Ajax, but you can’t please everyone.
Next there was a brief outline of the philosophy behind Ajax, which centers on the idea of not bothering the server any more than is necessary. The goal is that of reducing, if not eliminating, the unload/reload cycleor “blink,” as some call it. The Ajax philosophy also includes the idea of making the client’s computer work for a living. After all, personal computers have been around in some form for close to 30 years; they should do some worktake out the trash, mow the lawn, or something.
Finally, I presented the three simple examples of how Ajax can be implemented. The first example, although not quite Ajax, does much to show something of the first attempts to implement a web application with the feel of a Windows application. Although it’s primitive by today’s standard, it is still better than 99 percent of the web pages out there today.
Using the XMLHttpRequest object, the second example is dead on as to what is expected from an Ajax application. Broken are the bonds that limit updates to the unload/reload cycle that has been confronting us on the Web since Day 1. In addition, XML plays well with the concept of reducing traffic.
The third and final example pushes Ajax to the current limits with the addition of XSLT to the mix. XSLT allows XML to be twisted and stretched into any conceivable shape that we can imagine. No longer are our creations limited to the parts that we can dig up here and there; we can make our own parts on demand.
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