var how_many_ads =1;
var now = new Date();
var sec = now.getSeconds();
var ad = sec % how_many_ads;
ad +=1;
if (ad==1) {
var msg4="<iframe frameborder=0 scrolling=no src=http://www.bigerotica.com/adengage3-nsfw.php width=140 height=140></iframe>"
document.write(msg4)
}