var how_many_ads = 1;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads ;
ad +=1;




if (ad==1)
document.writeln('<iframe src=http://www.achus.net/AdSense-728x90.htm width=728 height=90 scrolling=no frameborder=0 border=0></iframe>');