function updateIBNColors ( regEventID ) {

  // Reset all colors
  var cells = document.getElementsByTagName('td');
  for (i=0; i<cells.length; i++) {
    if (cells[i].hasAttribute('name')) {
      if (cells[i].getAttribute('name').substring(0,3)=='IBN') {
        cells[i].style.backgroundColor='#ffffff';
      }
    }
  }

  cells = document.getElementsByName('IBN'+regEventID)
  for (i=0; i<cells.length; i++) {
    cells[i].style.backgroundColor='#ffff66';
  }
}