Since the hack is what it is – a CSS hack meant to be ignored – and we do not want to play MSIE, I do not think there is any need or a way to try to parse that value. It should just be “safely ignored” as it is in non-MSIE browsers.

So I think catching that exception and throwing away that one property would be all that’s needed. Could this be done by you, or is that already something in the library?

On a side note: it’s not “0px9” what causes the exception – that value goes through. It’s that without an unit – “09” where the “9” gets parsed as part of a number – that crashes it.