var how_many_ads = 3;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;

if (ad==1) {
url="cce_cigano.shtml";
alt="";
banner="cce_ran_1.gif";
width="140";
height="183";
}

if (ad==2) {
url="cce_runas.shtml";
alt="";
banner="cce_ran_2.gif";
width="140";
height="183";
}

if (ad==3) {
url="cce_quirologia.shtml";
alt="";
banner="cce_ran_12.gif";
width="140";
height="183";
}