Computer keyboard plays 2½ octaves at once:
lower whites Z X C V B N M /
lower blacks S D G H J,
upper whites Q W E R T Y U /
upper blacks 2 3 5 6 7,
plus high notes I 9 O 0 P.
← / → (or [ ]) shift the octave.
Tab through the keys, then Enter to play the focused
note.
Hold Space for sustain.
Plug in a MIDI keyboard and it just works (Chrome/Edge).