var playingUIDs = new Array();

function currentPlaying()
{
  return playingUIDs;
}

function registerPlaying(uid)
{
  playingUIDs.push(uid);
}

function unregisterPlaying(uid)
{
  index = playingUIDs.indexOf(uid);
  if(index != -1)
  	playingUIDs.splice(index,1);
}