Until we get rid of most IE versions, we can't really reliably produce animation in web applications. I have built a very simple image cross-fade effect. I most of my time making it IE compatible.
My point, though not complaint, was that it's more geared towards executing a single animation against a single DOM element or a group of DOM elements. This is incredibly powerful, but when you want to start chaining animations, or "firing" off additional animations when you're mid cycle on your first animation - it gets tricky.
For example doing something like...
$("#myDiv").animate({top: 50}, 1000, function(){ $("#myDiv").animate({left: 50}, 1000) });
Would move "myDiv" down from 0 to 50 over 1 second and then move it right from 0 to 50 over 1 second. But if I wanted to trigger the left -> right animation midway between the top -> bottom animation there isn't an easy way to do that as far as I know. Currently you'd have to create two top -> bottom animations and split up the distance and duration so you can interject the secondary animation.
$("#myDiv").animate({top: 25}, 500, function(){ $("#myDiv").animate({left: 50}, 1000); $("#myDiv").animate({top: 50}, 500) });
That or just execute the 2nd one with a timeout independent of the first...
$("#myDiv").animate({top: 50}, 1000); window.setTimeout($("#myDiv").animate({left: 50}, 1000), 500);
Neither of those "solutions" are terribly difficult, but it gets more and more complex when you start building on it. If Adobe's EDGE or another set of tools would give you the ability to do this easily, I'd happily pay for it. Anyway, I suppose I'm getting off topic. :)
TL;DR: Doing animations in web applications is hard for all the wrong reasons.