Web IDE

Great - thanks for letting us know! Strange though... I wonder why your computer was different, as most Macs seems to work without trouble.

With the button, did you try:

For the external button, after using 'pinMode(B4, "input_pulldown");', does 'digitalRead(B4)' return 0 when not pressed and 1 when pressed?

You could always try using a different pin, just to make sure?