function random_ad(how_many_ads, url1, img1, url2, img2, url3, img3, url4, img4, url5, img5) {


  var now = new Date()
  var sec = now.getSeconds()
  var ad = sec % how_many_ads;
  ad +=1;


  if (ad==1) {
    url=url1;
 
    banner=img1;
  }

  if (ad==2) {
    url=url2;

    banner=img2;
  }

  if (ad==3) {
    url=url3;

    banner=img3;
  }

  if (ad==4) {
    url=url4;
 
    banner=img4;
  }

  if (ad==5) {
    url=url5;

    banner=img5;
  }

  str="<center><a href='" + url + "' target='_blank'><img src='" + banner + "' border=0></a></center>";

  document.write(str);
}