if (document.images) {
  var newsoff = new Image()
  newsoff.src = "../images/b_news_dark_off.png"
  var newson = new Image()
  newson.src = "../images/b_news_dark_on.png"
  var resourcesoff = new Image()
  resourcesoff.src = "../images/b_resources_dark_off.png"
  var resourceson = new Image()
  resourceson.src = "../images/b_resources_dark_on.png"
  var literatureoff = new Image()
  literatureoff.src = "../images/b_literature_dark_off.png"
  var literatureon = new Image()
  literatureon.src = "../images/b_literature_dark_on.png"  
  var miniatureoff = new Image()
  miniatureoff.src = "../images/b_miniature_dark_off.png"
  var miniatureon = new Image()
  miniatureon.src = "../images/b_miniature_dark_on.png"
  var galleryoff = new Image()
  galleryoff.src = "../images/b_gallery_dark_off.png"
  var galleryon = new Image()
  galleryon.src = "../images/b_gallery_dark_on.png"
  var registryoff = new Image()
  registryoff.src = "../images/b_registry_dark_off.png"
  var registryon = new Image()
  registryon.src = "../images/b_registry_dark_on.png"
  var forsaleoff = new Image()
  forsaleoff.src = "../images/b_forsale_dark_off.png"
  var forsaleon = new Image()
  forsaleon.src = "../images/b_forsale_dark_on.png"
}
var isMenuAct = false; // the menu is not active yet

function actMenu(img1, img2) {
  isMenuAct = true // the menu is now active
  act(img1)
  inact(img2)
}

function inactMenu(img1, img2) {
  isMenuAct = false // the menu is no longer active
  if (document.images) {
    inact(img1)
    timerID = setTimeout('if (!isMenuAct) act("' + img2 + '")', 1)
  }
}

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

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