iOS support

Can you confirm this works on iOS?

I tried setting progressElement.value = 50; though it doesn't seem to do anything on iOS 5.1.

Thanks!

[kangax]

@LeaVerou Hey Lea, is there a chance to add support for indeterminate state on non-supported browsers? TIL iOS does not support it (including 8), which sucks. I imagine some clever CSS could do the trick to reproduce something akin to Chrome's rendering. The only issue — detecting lack of support without sniffing; not sure about that.