I tried using the AudioContext API to make the most primitive browser-based multi-voice chiptune tracker conceivable. No frameworks or external dependencies were used, and the page source ought to be very readable.

Songs are written in plain, 7-bit safe text. Every line makes a voice/channel.

The examples given on the page should hopefully illustrate every feature, but as a quick overview: Sounds are specified using Anglo-style note names, with flat (black) keys being the lowercase version of the white key above so as to maintain one character per note. Hence, a full chromatic scale is AbBCdDeEFgGa. Every note name is interpreted as the closest instance of that note to the preceding one. +- skips up or down an octave, ~ holds the previous note for a beat, . skips a beat, 01234 chooses one of 5 preset timbres, <> makes beats slower or faster (for all channels), () makes the current channel louder or quieter. All other characters are ignored.

If you come up with a good tune, please share it in the comments!