So, summarizing, now keyboard no longer works but it did in the past, regardless if joystick is connected or not. That is strange. You could make a test however by starting the browser with/without gamepad connected. On my Ubuntu 16.04 and OSX 10.11.4 both with Chrome 66.0.3359.139 (64 bit) it works. Have no 64 bit windows box for test.
Yes, that is correct, the keyboard worked a month ago when I played the game for the first time but it no longer works. Maybe a browser update broke something?
I already tried starting the browser with and without the gamepad connected. Same results. Thanks for helping me out.