window.onload =rotate;

var adImages = new Array("images/log-znoc2.jpg", "images/log-znoc1.jpg" ,"images/log-znoc3.jpg", "images/log-znoc4.jpg", "images/log-znoc1.jpg"); 
var thisAd = 0;

function rotate() {
  thisAd++
  if (thisAd == adImages.length) {
    thisAd = 0;
  }
  document.getElementById("adBanner").src = adImages[thisAd];
  setTimeout("rotate()", 3 * 2000);
}