y=0;
ad=new Array(y);
var bnum=new Number(Math.floor(99999999 * Math.random())+1);

//ad[y++]='<a href="http://www.astrolabio.net/adserver/adserver-alfa.cgi?' + bnum + '+N=URL" target="_blank" onMouseOver="window.status=\'<<< Click Aqui ! >>>\'; return true" onMouseout="window.status=\'\';return true;"><img border="0" src="http://www.astrolabio.net/adserver/adserver-alfa.cgi?' + bnum + '+N=IMG" alt="Haga Click Aqui !" width="468" height="60"></a>'
//ad[y++]='<iframe src="http://xf3s100.com/?adv=CE13EU&l=es&size=250&bc=ec" width="250" height="250" scrolling="no" frameborder="0"></iframe><br>'
ad[y++]='<IFRAME FRAMEBORDER=0 MARGINWIDTH=0 MARGINHEIGHT=0 SCROLLING=NO WIDTH=250 HEIGHT=250 SRC="http://ad.yieldmanager.com/st?ad_type=iframe&ad_size=250x250&section=2620"></IFRAME>'

x = Math.floor(Math.random()*(y));
document.write(ad[x]);