number_of_banners=5;

var sctr=0;
var halt=0;
var isn=new Array();
for (i=0;i<number_of_banners;i++){
 isn[i]=new Image();
}

isn[0].src="images/banner1as.jpg";
isn[1].src="images/banner1as.jpg";
isn[2].src="images/banner2as.jpg";
isn[3].src="images/banner3as.jpg";
isn[4].src="images/banner4as.jpg";

function rotateIt(){
 if (halt!=1){
  sctr++;
  if (sctr>number_of_banners-1){
   sctr=0;
   }
  document.banners.src=isn[sctr].src;
  setTimeout("rotateIt()",15000);
  }
 }