Tero Parviainen
On Web MIDI enabled browsers (i.e. Chrome) you can select a connected MIDI device from above and produce sounds externally.
When using MIDI, messages for each instrument are sent on separate MIDI channels: 1, 2, 3, and 4. Percussion is sent on channel 7.
You can use the mouse to click on any measure to switch to it, or pan around by dragging.
Tero Parviainen