How can retrieve midi message port information

Dealing with this code :

    function(midiAccess)
    {
        midiaccess = midiAccess;
        midiPluginsStatus = 1;
        midiInputs = midiaccess.inputs;
        midiOutputs = midiaccess.outputs;
        $('#MIDI-status').html('ACTIVATED');
        listInputsDevices();
        listOutputsDevices();
        var inputs = midiAccess.inputs.values();
        for(var input = inputs.next(); input && !input.done; input = inputs.next()){
            input.value.onmidimessage = onMIDIMessage;
        }
        midiAccess.onstatechange = onStateChange;
    },

I can retrieve easily the MIDI message hexa. Ok with this I can know lot of things (note on, CC, PG etc...) but how can I retrieve the port of this midi message event ?

I would like to know where do you from the MIDIMessage

My question was for retrieve port information without other any adding code inplementation. But just with API.

The missunderstanding of this API is that for knowing information about MIDI message you know previously listening the port. If you don't know the port You never can retrieve this information.

The only solution I found is that listening all the port in the same time and AFTER when I received MIDI information I can retrieve port information of unknow message.

This is just a inverse logic of understanding.

Concentrate all the message listening all the port on the same function which retrieve information detail. As an monitor MIDI...