Thanks for the feedback all. Unfortunately each browser seems to have its quirks in the implementation of the spec - I thought I'd caught most of them but obvio

Thanks for the feedback all. Unfortunately each browser seems to have its quirks in the implementation of the spec - I thought I'd caught most of them but obviously still a bit of work to do! With regard to the dial rotating rather than the needle, it's an interesting point (no pun intended :) I think each has its own merit for certain applications - probably worth adding an option to choose.