function shuffle(l) {
  var plucked = [],
      len = l.length;
  while (plucked.length < len) {
    var idx = parseInt(Math.random() * l.length);
    plucked.push( l.splice(idx, 1)[0] );
  }
  return plucked;
}

var l = [1,2,3,4,5];
l = shuffle(l);