It seems that Opera wants to render all the CSS/DOM
changes before applying further changes. When JSAV
moves to the beginning or end of the animation, it
applies all the CSS/DOM changes in each step of the
recorded sequence. Other browsers seem to optimise
this a bit so that they donât render the changes
immediately but instead only render the state at the
beginning/end of the animation. Or, alternatively,
they have much faster renderers than Opera.
From our discussion: