function so_xfade() {
	count++;
	cOpacity = xOpacity(currentImg);
	nOpacity = xOpacity(nextImg);
	cOpacity-=.05; 
	nOpacity+=.05;
  if(nOpacity > .99){
    xGetElementById(currentImg).src = "./images/trucc.gif";
    xGetElementById(currentImg).style.display = 'none';
    return ;
  }
  else{
    xOpacity(currentImg, cOpacity);
    xOpacity(nextImg, nOpacity);    
    setTimeout('so_xfade()', 50);//in IE7 l'infame impazisce passando dei parametri !!!
  }
}
// xOpacity, Copyright 2006-2007 Michael Foster (Cross-Browser.com)
// Part of X, a Cross-Browser Javascript Library, Distributed under the terms of the GNU LGPL
function xOpacity(e, o)
{
  var set = xDef(o);
  //  if (set && o == 1) o = .9999; // FF1.0.2 but not needed in 1.5
  if(!(e=xGetElementById(e))) return 2; // error
  if (xStr(e.style.opacity)) { // CSS3
    if (set) e.style.opacity = o + '';
    else o = parseFloat(e.style.opacity);
  }
  else if (xStr(e.style.filter)) { // IE5.5+
    if (set) e.style.filter = 'alpha(opacity=' + (100 * o) + ')';
    else if (e.filters && e.filters.alpha) { o = e.filters.alpha.opacity / 100; }
  }
  else if (xStr(e.style.MozOpacity)) { // Gecko before CSS3 support
    if (set) e.style.MozOpacity = o + '';
    else o = parseFloat(e.style.MozOpacity);
  }
  else if (xStr(e.style.KhtmlOpacity)) { // Konquerer and Safari
    if (set) e.style.KhtmlOpacity = o + '';
    else o = parseFloat(e.style.KhtmlOpacity);
  }
  return isNaN(o) ? 1 : o; // if NaN, should this return an error instead of 1?
}