playing the C scale
[change]

mouse controls:

hover = play note
click = stop all noises

keyboard controls: (piano mapping)

black keys = {2 3 5 6 7 9 0 =}
white keys = {q w e r t y u i o p [ ]}

black keys = {s d g h j l ;}
white keys = {z x c v b n m , . /}

only tested on recent Chrome and Firefox browsers. Definitely not mobile friendly.