function actMenuItem(imgName) {
  act(imgName);
  //inact(defImg);
}

function inactMenuItem(imgName) {
  inact(imgName);
  //act(defImg);
}

function act(imgName) {
  if (document.images)
    document.images[imgName].src = eval(imgName + "on.src");
}

function inact(imgName) {
  if (document.images)
    document.images[imgName].src = eval(imgName + "off.src");
}