Move html elements positions slow on iOS
===

I have a huge performance issue on iOS html5 webapp when I modify the position of multiple html elements in CSS. I would like also to move manually my elements. I do not want to use CSS transformation because it is not possible to stop the animation (we are making a highly responsive game).   

My example works fine on a desktop browser (chrome, firefox, etc.), on Android. But it is very slow on an iPad 2 and an iPhone 4S (both running iOS 5.1).
Running the html5 code in a Phonegap app is better than directly in the browser but is still slow.

What do you suggest to improve things?  
[editable example][1]  
[full screen example][2]


  [1]: http://jsfiddle.net/JLGYY/4/
  [2]: http://jsfiddle.net/JLGYY/4/embedded/result/