Processing.js is quite something. Its a port of the Processing data visualisation programming language into Javascript. A great use of the <canvas> functionality in recent browsers. Because it pushes the browser to it’s maximum, it is recommended you use it only with the latest beta browsers: Firefox 3, WebKit nightlies and Opera 9.5.
If this doesn’t sound impressive to you, check out some of the demos:
There really are all kinds of things from physics to fractals, from clocks to modern art.
What can I say apart from that it’s left me speechless and quite how processing.js can weigh in at over 5000 lines and compresses to under 10kb.
I suppose the sluggish performance in the browsers is the main downside of this but I guess that this will get better in time as I haven’t seen enough intensive <canvas> applications lying about which would warrant browser makers putting time into improving performance.