var links = ["http://www.middlebass.org/sothebys/","http://www.sthazards.com/middle-bass-island-ads.php","http://www.myauntirmas.com/", "http://www.middlebassisland.info","http://www.middlebassinn.com/index.html"]; // link addresses
var imgs = ["http://www.middlebass.org/images/wADsothebys.jpg","http://www.middlebass.org/images/HazardsLodging.jpg","http://www.middlebass.org/IrmasAdLogoJ.jpg","http://www.middlebass.org/images/RealEstate2.gif","http://www.middlebass.org/images/MBI_Inn_Ad.jpg"]; // link images
var img = []; // preloading array
var len = links.length; // length

var timeBasis = 5; // in seconds 
   // preload images
      for(i=0; i<imgs.length; i++){
         img[i] = new Image();
         img[i].src = imgs[i];
      }

function showAd(){
   if(len == 0){
            document.write('<img src="blank.gif" alt="">');
         return false;
      }
   var rand = Math.floor(len*Math.random());

   document.write('<a href="'+links[rand]+'" title="Go to '+links[rand]+'" id="myAd">');
   document.write('<img src="'+img[rand].src+'" alt="Go to '+links[rand]+'" name="myAdImg"></a>');
   setInterval("updateAd()", timeBasis*1000);
}

function updateAd(){
   var r = Math.floor(len*Math.random());
      if(!document.links) return false;
         for(i=0; i<document.links.length; i++){
            if(document.links[i].id == "myAd"){
               if(document.links[i].href != links[r]){
                  document.links[i].href = links[r];
                  document.images['myAdImg'].src = img[r].src;
         } else {
               updateAd();
         }
       }
     }
}