var ran_number=Math.floor(Math.random()*9); 

var ad_url=new Array(5)
     ad_url[0]="<a href=http://rdent.com><img src=img/rd.gif width=234 height=60 border=0 title='r.d. enterprises, ltd. - Lotus Parts Specialists'></a>";
     ad_url[1]="<a href=http://www.banks-europa.co.uk><img src=img/ee.gif width=234 height=60 border=0 title='Europa Engineering'></a>";
     ad_url[2]="<a href=http://www.jaeparts.com/><img src=img/jae.gif width=234 height=60 border=0 title='JAE Lotus Parts'></a>";   
     ad_url[3]="<a href=http://www.davebean.com><img src=img/dbe.gif width=234 height=60 border=0 title='Dave Bean Engineering'></a>";
     ad_url[4]="<a href=http://www.sportscarworld.com><img src=img/scw.gif width=234 height=60 border=0 title='Sports Car World'></a>";
     ad_url[5]="<a href=http://www.lotus-central.com><img src=img/lc.gif width=234 height=60 border=0 title='Lotus Central Partner Banner'></a>";
     ad_url[6]="<a href=http://www.myvrl.com><img src=img/vrl.gif width=234 height=60 border=0 title'=The Vintage Racing League'></a>";
     ad_url[7]="<a href=http://www.kampena.com><img src=img/kamp.gif width=234 height=60 border=0 title'=Kampena Motors'></a>";
     ad_url[8]="<a href=http://www.colinchapmanmuseum.org.uk><img src=img/museum.gif width=234 height=60 border=0 title'=Chapman Museum'></a>";
  
document.write(ad_url[ran_number]);