var how_many_ads = 4; // change this depending on the number of banners
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;

if (ad==1) {
url="http://www.shareasale.com/r.cfm?b=13621&u=94808&m=4019&urllink=&afftrack=turtlesite";
banner="http://www.shareasale.com/image/pets-turtle.gif";
alt="Shop at Pets-Warehouse.com";
}
if (ad==2) {
url="http://www.tkqlhce.com/97115vpyvpxCEHKLHJKCEDHEHIIK?cm_mmc=CJ-_-468330-_-1478467-_-468%20Free%20Shipping%20Store%20Banner";
banner="http://www.lduhtrp.net/oj105c37w1-LNQTUQSTLNMQNQRRT";
alt="Shop at Petco.com";
}
if (ad==3) {
url="http://www.shareasale.com/r.cfm?b=73399&u=94808&m=11235&urllink=&afftrack=turtlesite";
banner="http://www.shareasale.com/image/coupon_10_off_468x60_v1.jpg";
alt="Shop at StuffedAnimals.com";
}
if (ad==4) {
url="http://www.shareasale.com/r.cfm?b=41095&u=94808&m=8334&urllink=&afftrack=turtlesite";
banner="http://www.shareasale.com/image/468x60_226.gif";
alt="Shop at PlayfulPlushToys.com";
}

document.write('<a href=\"' + url + '\" target=\"_blank\">');
document.write('<img src=\"' + banner + '\" alt=\"' + alt + '\" width=468 height=60 border=0></A>');