Playing with RequestAnimationFrame

External references:

Here is a link to this doc - useful for seeing whether requestAnimationFrame is getting called if you open this page in a new (background) tab.

Browser behaviour

Browser Regular page Page opened in another tab
Chromium 19 (Win) Runs at ~60fps; stops running when you switch to another tab; restarts when you switch back Doesn't start running until you switch to that tab
Firefox 10 (Win/Lin) Runs at ~60fps; goes very slow when you switch to another tab; restarts when you switch back Runs very slowly, gradually getting slower, runs normally when you switch to the tab
Safari 5.1.2 (Win) NO IMPLEMENTATION OF REQUESTANIMATIONFRAME
Opera 11.61 (Win) NO IMPLEMENTATION OF REQUESTANIMATIONFRAME (not in Opera Next 12.0 either)
IE9 (Win) NO IMPLEMENTATION OF REQUESTANIMATIONFRAME (in IE10 according to caniuse.com)

The Firefox throttling back behaves as follows:

Invocation # Seconds
1 1
2 3
3 7
4 15
5 31
6 63
7 127

Debug messages will appear here