We should support animation of CSS gradient values (i.e., -moz-linear-gradient, -moz-radial-gradient) in nsStyleAnimation.
There's still some open debate on how animation of gradients should work.
(I don't have work in progress on this, but I'm trying to get bugs filed on animation/transition work that should happen for 3.7.)
See also bug 536541 on SVG gradients.
Gradient interpolation is now defined by the spec: http://www.w3.org/TR/css3-images/#interpolating-gradients
/me want to help.
But i do not know where to start.
I need to animate the -moz-radial-gradient.
Created attachment 8755319 [details]
Created attachment 8755320 [details]
Created attachment 8755321 [details]
In this test case:
* IE10 has supported gradient animation.
* Chrome and Safari has supported image animation(Like cross-fade()).
* Firefox at least should do a simple transition(direct display of different images), rather than nothing.
Related animation how to calculate the spec here, The current spec is already CR.