SO TOTALLY HELPFUL!
I learned about AJAX in C5 by downloading this module and playing around with it. John did a great job creating a minimalist set of content that exhibits the key approaches to invoking behavior without requiring a page refresh. It's clean, the comments explain what to expect and how to use it - it's really a beautiful tool.
Ajax is one of those terms that IMHO is at its core, simple, but as soon as you start to try implementing it there's a billion different ways to skin the cat. Having the basic experience from this lesson goes a LONG way towards choosing reasonable implementation strategies. Of course you'll learn more as you progress in trying to build your own, but this will give you a terrific leg up.
Thank you John!
Brilliant -- exactly the information I needed, summarized in a visual way. 5 stars for saving me tons of time.
Heed the advice and don't use this on a real site. Also, once you install it on a test site, do not try to "Add Page" as I did, it doesn't work. Go directly to "Edit Page". Then select any area and "Add Block". Then scroll and select one of the 2 "AJAX lessons" blocks to learn about. You can click the links to see what happens on the popup. But no block actually gets added to your area. You'll just close the pop up window or refresh. But after reading and seeing what happens when you click the links, then you can go look for the files in the directory and see the code for yourself.
Loved it! Thanks!
EDIT: Actually if you scroll down far enough you'll see the button which does indeed add the block if you want it, I missed it the first time.