It appears to be Chrome only which might explain your problem with controls...
Edit: Yes, I did only test in Firefox and Chrome. According to the comments below, it appears to work for modern browsers except Firefox.
Edit: Yes, I did only test in Firefox and Chrome. According to the comments below, it appears to work for modern browsers except Firefox.
I can't understand this - in 2013, how on earth do you break mouse events in JavaScript? We've had events like onmousedown working reliably across browser implementations for a decade or more, what on earth is going on?
Firefox should just support offsetX as well, but they don't, for whatever reason.