The MIDIOutput interface of the Web MIDI API provides methods to add messages to the queue of an output device, and to clear the queue of messages.

This interface doesn't implement any specific properties, but inherits properties from MIDIPort.

This interface also inherits methods from MIDIPort.

MIDIoutput.send()

Queues a message to be sent to the MIDI port.

MIDIOutput.clear()

Clears any pending send data from the queue.

The following example sends a middle C immediately on MIDI channel 1.

function sendMiddleC(midiAccess, portID) {
  const noteOnMessage = [0x90, 60, 0x7f]; // note on, middle C, full velocity
  const output = midiAccess.outputs.get(portID);
  output.send(noteOnMessage); // sends the message.
}