issue with sending event data with click over socket.io

Forgive me, I've been learning node and js over the last few days, come from C#/unity and everything is a little bit different from what I know. I'm making a collaborative drum machine, I've got 90% working: http://ec2-54-194-29-66.eu-west-1.compute.amazonaws.com:9000/

I have the node server working, with key presses being sent and mouse co-ords, however I have an issue with mapping a mouse click event, I am registering the click in console of other connections and server, but seems I don't quite understand sending the contents of events properly. I can't write var data = list: e.classList and read data.list to do the see the same thing?

Here's code I've been trying to get working, but I get cannot read property error:

    function newMouseOn(data)
    {
        console.log("Is this working Click On?" + data.target);
        data.list.add('active');
        //clickPlayOn(data);
        data.target.play();
    }

    function newMouseOff(data)
    {
        console.log("Is this working ClickOff?" + data.target);
        //clickPlayOff(data);
        data.list.remove('active');
    }   

socket.on('mouseOn', newMouseOn);
socket.on('mouseOff', newMouseOff);


  function clickPlayOn(e)
    {
       var data = {
         id: e.target.id,
         timeStamp: e.timeStamp,
         type: e.type,
         target: e.target,
         list: e.classList
       }
        socket.emit('mouseOn', data);
        e.target.classList.add('active');
        e.target.play();
    }

    function clickPlayOff(e)
    {
      var data =
      {
        id: e.target.id,
        timeStamp: e.timeStamp,
        type: e.type,
        target: e.target,
        list: e.classList
        }
        socket.emit('mouseOff', data);
        e.target.classList.remove('active');
    }


server side: 

  socket.on('mouseOn', MouseClick);
  socket.on('mouseOff', MouseClicked);


function MouseClick(data)
  {
    socket.broadcast.emit('mouseOn', data);
    console.log(data);
  }

  function MouseClicked(data)
  {
    socket.broadcast.emit('mouseOff', data);
    console.log(data);
  }

I was originally trying to just emit e or e.target instead of that data struct, but that didn't seem to work. Has anyone got any ideas on what I'm missing? (other than a brain)