Thanks, it worked.
But raw action needs to be deleted; if Baked Animation is deleted, only parts(bone) with keyframes are moving.

BTW You made great and powerful product! Keep up the good work!

Thanks, will try it.
I will have bunch of similar scenes with various products, this is the first one.
My idea was to be able to pull the parts by mouse and when released, it returns to "rest" position (with dynamics) but I lack knowledge how to do it, so I made a compromise with animation

Thanks,

Meanwhile I put scene online:
B4W Scene

..and here is .blend source
Blend file

I made scene with 2 separate armatures and 2 animation which get played by press of 2 separate buttons.
second press on button stops that animation.
Something like one here (but with bones animation):
https://youtu.be/rdXHaZ1tAeY
However I run into a problem, on second press animation stops in ie frame 45, when I press button again it plays from beginning making visible "jump".
Both animations are cyclic (or ping-pong to be precise).
I tested it only on 1 bone and it worked as it should. it continued animating.
Using latest blend4web 16_08…
Is there some workaround? or I am just missing something?