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Thursday, September 15, 2005

  2:38 PM - Ajax por accidente
It seems that, unbeknownst to me, I delivered an Ajax application last fall.

Ajax is a technical approach based on Asynchronous JavaScript and XML. It leverages the XML HTTP Request object (available from most browsers in some form) in asynchronous mode, along with timers, events, DHTML, and JavaScript to provide a smooth, responsive user experience.

This is the approach that Google used extensively in its map interface. It is how Google Maps downloads new content in the background to provide the seamless panning and other nice interactions. However, on a different scale, this is the same thing that we did in a custom HTML based Tracking Server / AVL client implementation to help a city manage its snow removal operations.

The difference is that Google did it on purpose and found ways to leverage Ajax throughout their application, whereas for us it was more of an ad-hoc design choice to solve a very specific problem. I took this approach to animate the ploughs, backhoes, and other equipment based on a live data feed from Tracking Server. Without Ajax, the application would have had to freeze every few seconds while it retrieved new data from the server. With Ajax, it's smooth and responsive.

Of course, when we did it, it didn't occur to us that the approach was anything novel, and we certainly wouldn't have guessed that it was going to get a high enough profile to be given a name. Google Maps wasn't even out at that time, so we hadn't yet seen how far it could be taken. Nevertheless, it's cool to find yourself ahead of the curve, and I plan to put these techniques to use "on purpose" in upcoming projects.
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