It'd alter too much normal onKeyDown, onKeyPress, onKeyUp:
Normal / current sequence (also in desktop firefox)
                           onKeyDown         onKeyPress         onKeyUp
event.keyCode         '13'                     '13'                      '13'
event.charCode         '0'                       '0'                        '0'
event.which              '13'                     '13'                      '13'


With youtube hack:
                            onKeyDown         onKeyPress         onKeyUp
event.keyCode         '13'                        '0'                       '13'
event.charCode         '0'                       '13'                        '0'
event.which              '13'                       '13'                      '13'