var cnt=50;
var speed=10;
var predelay=2000;

function fadeout() {
window.setTimeout("ausblenden(cnt,speed)", predelay); }

function ausblenden() { cnt--;
if(cnt>=0) { setOpacity(cnt,"intro"); window.setTimeout('ausblenden()', speed); } } 

function setOpacity(value,ref) {
document.getElementById(ref).style.opacity=value/50;
document.getElementById(ref).style.filter='alpha(opacity=' + value*50 + ')'; }