You look up a sorting algorithm on Wikipedia, and there's a handy animated GIF on the page; but it's hard to follow because it goes at a strange pace. Alas! If only you had some way of stopping the animation and going through it frame-by-frame...
You have this hilarious animation of a cat doing a funny thing; but it would be 3½ times as hilarious if only it was playing in reverse. Alas! If only there was some way you could do that without leaving the comfort of your web page...
jsgif an animated GIF player bookmarklet with support for pausing, going frame-by-frame, playing in reverse, and other features that one might expect from a video player.
Unfortunately, the DOM doesn't expose individual frames of a GIF, so this is done by downloading the GIF (with XMLHttpRequest), parsing it, and drawing it on a <canvas>.
Featuring Windows 3.11-style graphics, Web 3.11-style rounded corners, and the world's least efficient LZW decoder, jsgif is the needlessly-convoluted animated GIF player of choice for those with more CPU cycles and RAM than they know what to do with.
Show info; reverse; previous frame; play/pause; next frame; pin/unpin; revert to GIF. "info" is the current frame and the delay per frame (both can be changed when paused).
You can figure it out.
You can email me at shachaf@gmail.com.