[bzbarsky]

It's actually not all that complicated.

Firefox 4 added mozRequestAnimationFrame.

Firefox 23 added the unprefixed version.

It's documented in the browser compatibility table at https://developer.mozilla.org/en-US/docs/Web/API/window.requ... (note that "moz" next to the 4.0).

[mzs]

That must have done the trick, it starts now, thank you for your help.