var how_many_ads = 2; 
var now = new Date() 
var sec = now.getSeconds() 
var ad = sec % how_many_ads; ad +=1;


if (ad==1) 
{ 
url="http://www.gmat-success.com/gmat-product.html" ; 
alt="GMAT Quantitative Software";
banner="http://www.litesee.com/images/big_banner_5.gif"; 
width="110"; 
height="300"; 
}

if (ad==2) 
{ 
url="http://www.gmat-success.com/gmat-product.html"; 
alt="GMAT Software";
banner="http://www.litesee.com/images/big_banner_6.gif"; 
width="110"; 
height="300"; 
}

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