albertein

var move = function(array, element, delta) {
  var index = array.indexOf(element);
  var newIndex = index + delta;
  if (newIndex < 0  || newIndex == array.length) return; //Already at the top or bottom.
  var indexes = [index, newIndex].sort(); //Sort the indixes
  array.splice(indexes[0], 2, array[indexes[1]], array[indexes[0]]); //Replace from lowest index, two elements, reverting the order
};

var moveUp = function(array, element) {
  move(array, element, -1);