Ted Goddard added a comment - 08/Mar/13 8:41 PM It may not be possible to achieve smooth performance on the blackberry, but the animations should be revisited. In particular, they are currently not timed correctly. I had performed some initial analysis in 2012: Judy presented some accordion animation techniques on wednesday, and I was interested in seeing how they worked. I've created two simplified pages (these only work on webkit to make the details easier to modify): http://tetra.ice/~tedg/panes/simple.html http://tetra.ice/~tedg/panes/simple-multi.html The difference between the two accordions is that one has fixed-size panels and the other has variable size panels. Since CSS animations are specified by time and not by speed, it is not possible to have variable-sized panels with only one open at the time (it is possible, but the animation looks very strange and would be distracting). In any case, there are uses for accordions in both modes: single and multiple panels open simultaneously. Some notes: we will need efficient and simple APIs for manipulating CSS attributes client-side, such as toggling one or many classes (note the use of "this" to simplify the onclick javascript) it's very easy to create bizarre looking animations, so the main customization by application developers would be timings simple.html makes use of data- attributes for storage – storing data in the DOM provides multiple instance scoping without complex state stored in JavaScript instances I don't see any issues with the transform animation, however, we should avoid transition: all since this could easily animate attributes that we do not need to animate (such as use-specified attributes) and is likely more performance intensive.