var m = new Array(0,100);
var t = new Array();

function next() {

m[0]+=1;
m[1]-=1;
document.getElementById("a2").style.filter="alpha(opacity="+m[0]+")";
document.getElementById("a1").style.opacity = m[1]/100;
document.getElementById("a1").style.filter="alpha(opacity="+m[1]+")";
document.getElementById("a2").style.opacity = m[0]/100;
t[0] = setTimeout("next()",5);
if (m[0]>98){

 clearTimeout(t[0])
 setTimeout("back()",5000)}

}


function back() {

m[0]-=1;
m[1]+=1;
document.getElementById("a2").style.filter="alpha(opacity="+m[0]+")";
document.getElementById("a1").style.opacity = m[1]/100;
document.getElementById("a1").style.filter="alpha(opacity="+m[1]+")";
document.getElementById("a2").style.opacity = m[0]/100;
t[1] = setTimeout("back()",5);
if (m[1]>98) 
{
clearTimeout(t[1])
setTimeout("next()",5000)
}
}