function doBanner(){
   var ad=new Array()
   ad[0]='';
   ad[1]='';
   ad[2]='';
   ad[3]='';
   ad[4]='';
   ad[5]='';
   ad[6]='';
   ad[7]='';
   var links=new Array()
   links[0]='';
   links[1]='';
   links[2]='';
   links[3]='';
   links[4]='';
   links[5]='';
   links[6]='';
   links[7]='';
   var xy=Math.floor(Math.random()*ad.length);
   if(links[xy]!=""){
      var nav = document.getElementById("topNavigation3");
      var link = document.createElement('A');
      var img = document.createElement('IMG');
      var urlRoot= window.location.protocol + "//" + window.location.host;
      if(window.location.toString().indexOf('buyacar/')>-1)urlRoot=urlRoot+"/buyacar"
      link.href=links[xy];
      link.title = "Click Here";
      link.id="pgTopB";
      img.src = urlRoot + "/images4/bannerimages/" + ad[xy];
      img.alt="buyacar advert";
      img.border="0";
      nav.parentNode.insertBefore(link,nav);
      link.appendChild(img);
   }
}   
doBanner();