function setBackgroundImage(elemID,imageURL)
{
  var elem = document.getElementById(elemID);
  if ( ! elem ) return true;   // Do default processing
  elem.style.backgroundImage = "url(" + imageURL + ")";
  return false;
}
function setText(elemID,text)
{
  var elem = document.getElementById(elemID);
  if ( ! elem ) return true;   // Do default processing

  var textNode = document.createTextNode(text);
  var idx;
  if ( ! elem.firstChild )
  {
    elem.appendChild(textNode);
  }
  else
  {
    for (idx=0; (child=elem.childNodes[idx]); ++idx)
    {
      if (child.nodeName == "#text")
      {
        elem.replaceChild(textNode, child);
        break;
      }
    }
  }
  return false;
}
function displayMenuItem(itemNum)
{
  setBackgroundImage("MenuPhoto", "/menu/" + itemNum + ".jpg");
  setText("MenuPhotoCaption", "Menu item " + itemNum);
  return false;
}