// Code for fading images
function setOpacity(obj, opacity) {
  if (opacity <= 0) {
    obj.style.visibility = "hidden"
    opacity = 0
  }
  opacity = (opacity >= 100)?99.999:opacity;
  // IE/Win
  obj.style.filter = "alpha(opacity:"+opacity+")";
  // Safari<1.2, Konqueror
  obj.style.KHTMLOpacity = opacity/100;
  // Older Mozilla and Firefox
  obj.style.MozOpacity = opacity/100;
  // Safari 1.2, newer Firefox and Mozilla, CSS3
  obj.style.opacity = opacity/100;
  if (opacity > 0) {
    obj.style.visibility = "visible"
  }
} 

function doFade(imgId, opacity, step) {  
  image = document.getElementById(imgId)
  opacity += step
  setOpacity(image, opacity)
  if (opacity > 0 && opacity < 100) {
    setTimeout("doFade('" + imgId + "'," + opacity + "," + step + ")", 40)
  }
}

function fadeIn(imgId, step) {
  doFade(imgId, 0, step)
}

function fadeOut(imgId, step) {
  doFade(imgId, 100, -step)
}

function crossFade(imgIdFrom, imgIdTo, step) {
  doFade(imgId1, 100, step);
  doFade(imgId2, 100, -step);
}