Called whenever a new MIDI port is added or an existing port changes state.
Examples
The Navigator.requestMIDIAccess() method returns a promise that resolves with a MIDIAccess object. Information about the input and output ports is returned.
When a port changes state, information about that port is printed to the console.
js
navigator.requestMIDIAccess().then((access)=>{// Get lists of available MIDI controllersconst inputs = access.inputs.values();const outputs = access.outputs.values();
access.onstatechange=(event)=>{// Print information about the (dis)connected MIDI controller
console.log(event.port.name, event.port.manufacturer, event.port.state);};});