Back then, I implemented a drag-scrollable zoomable fractal viewer in Javascript from first principles. This involved doing all the crufty cross-browser compatibility work myself, which was really annoying and very nearly took all the fun out of the project. Recently, after playing with jQuery a bit, I thought it would be good to go back to the fractal viewer and reimplement it using jQuery.
You can see the results of my efforts at my Mandelbrot set viewer.
The controls are pretty much what you'd expect. Panning and dragging work as expected (but sometimes you have to wait for the tile server to keep up). The zoom control zooms in 2x for each step, with an effective upper bound limited only by the floating point precision of Javascript. Double-clicking zooms in 2x on a particular point on the plane. The currently-unlabeled button below the zoom control allows you to generate a larger (desktop-sized) snapshot of your current view.
I was talking to Phil today who suggested I look at OpenLayers. Sure enough, in their Gallery there is already a Fractal Browser which does almost exactly the work that I've already done!
Once again, somebody out there on the internet has already thought of the same idea. Nevertheless, I'm happy with my viewer (even though it's not everything I had envisioned yet) and I think I'll leave it as is and move along to something else. Finally, because this is Open Source Wednesday, you can find the code in ghewgill/mandelbrot on GitHub. Enjoy!