It's really requested a lot. I'll add this asap.

I can make a PR if you want or do you prefer to do it?

Ok, I might modify it a bit but will surely save time.
Thanks

@flesler little question. At the moment the done callback is only fired when the animation completes. This means that if stop() is called, it will never be called.

With the interrupt option, do you want the callback to be called when the animation is interrupted or not?

If not, we could make interrupt a boolean as well as a function. If a function is passed, it would be called instead of the callback.

Or.. add a onStop/onInterrupt similar to jQuery.

I thought of that as well when thinking about this issue, I'm not sure.
I'll think about this when I start coding the solution. Adding additional callbacks is a feasible approach, making interrupt a boolean/function is clever but kind of inconsistent on the naming, as the end callback is called onAfter (and onBefore on localScroll and serialScroll).

What do you think.

I think adding onStop is better. It would be called on interrupt or if .stop() is called programmatically during the animation. I already got it working. Tomorrow I will make a PR for you to review or take ideas.

This seems to work in Chrome: https://stackoverflow.com/questions/4034659/is-it-possible-to-animate-scrolltop-with-jquery/20699124#20699124

This is implemented. To cancel on user scroll pass {interrupt:true}, if you want a callback that is called when the scroll is interrupted, you can pass a fail callback that is provided natively by jQuery. You can check the demo I updated it with an example of both settings.