hi,
a revolute joint can be static ( like a nail pinned on a wall ) or moving (like a car and its rotating wheels)

static revolute joint:

create 1 body (square, circle, image or text) , create the revolute joint on the body you just created, adjust positions of body and/or revolute joint ( they'll remain connected even if not overlapping) press play !

moving revolute joint:

create 2 overlapping bodies (square, circle, image or text) , create the revolute joint on the overlapping area adjust positions... press play !

Revolute joint can be a rotating motor: check the "specific" parameters.

:)

@X.
you're right
I will try to fix this on firefox

Thanks

EDIT : This is fixed on firefox, thank you for the feedback ;)

Is there code documentation any whare? If so I can't find it.