function scrollUpDown (direction, objid)
{
var obj = document.getElementById(objid);
var delta = 50;
	var mtop = parseInt(obj.style.top);
	if (isNaN(mtop)) mtop = 0.0;

	if (direction == 'U')
		mtop = mtop + delta;
	else if (direction == 'D')
		mtop = mtop - delta;

	if (mtop > 0) mtop = 0.0;

  obj.style.top = mtop + 'px';
  return true;
}