Exercise 40 answer doesn't work in firefox

[krivulcik]

The sample answer for Exercise 40 doesn't work in firefox because of https://bugzilla.mozilla.org/show_bug.cgi?id=112379 .

The code uses String.fromCharCode(e.keyCode) where e is keypress event. Firefox uses charCode for events which generate characters.

[krivulcik]

After changing the event in verifier from keypress to keyup, the exercise works in firefox, but the registered characters are converted to upper case. The exact same thing happens in Exercise 42, both in firefox and chromium - the verifier uses keyup event in Exercise 42.