tag=new Array();

tag[0]='<iframe frameborder="0" allowtransparency="true" height="60" width="468" marginheight="0" scrolling="no" src="http://ad.jp.ap.valuecommerce.com/servlet/htmlbanner?sid=2608878&pid=878673021" marginwidth="0"><script language="javascript" src="http://ad.jp.ap.valuecommerce.com/servlet/jsbanner?sid=2608878&pid=878673021"></script><noscript><a href="http://ck.jp.ap.valuecommerce.com/servlet/referral?sid=2608878&pid=878673021" target="_blank" ><img src="http://ad.jp.ap.valuecommerce.com/servlet/gifbanner?sid=2608878&pid=878673021" height="60" width="468" border="0"></a></noscript></iframe>';

i=Math.floor(Math.random()*tag.length);  
document.write(tag[i]);