function banner(img_source,url,alt,chance) {
   this.img_source = img_source;
   this.url = url;
   this.alt = alt;
   this.chance = chance;
}
function display() {
   with (this) document.write("<A HREF=" + url + "><IMG SRC='" + img_source + "' WIDTH=468 HEIGHT=60 BORDER=0 ALT='" + alt + "'></A>");
}
banner.prototype.display = display;
banners = new Array();
banners[0] = new banner("http://webkatalogus.wqw.hu/bannerek/wqw_webkatalogus468X60.png",
                        "http://webkatalogus.wqw.hu/ target='_blank'",
                        "WQW webkatalógus",
                        10);
banners[1] = new banner("http://www.mozi-dvd.hu/mozidvd468x60.jpg",
                        "http://www.mozi-dvd.hu/ target='_blank'",
                        "Mozi-DVD filmek",
                        10);
banners[2] = new banner("http://london.wyw.hu/banners/magyaroklondonban.gif",
                        "http://www.magyaroklondonban.com target='_blank'",
                        "Magyarok Londonban - London-Budapest", 
                        10);
sum_of_all_chances = 0;
for (i = 0; i < banners.length; i++) {
   sum_of_all_chances += banners[i].chance;
}
function display_banner() {
   chance_limit = 0;
   randomly_selected_chance = Math.round((sum_of_all_chances - 1) * Math.random()) + 1;
   for (i = 0; i < banners.length; i++) {
      chance_limit += banners[i].chance;
      if (randomly_selected_chance <= chance_limit) {
         document.write("<A HREF=" + banners[i].url + "><IMG SRC='" + banners[i].img_source + "' WIDTH=468 HEIGHT=60 BORDER=0 ALT='" + banners[i].alt + "'></A>");
         return banners[i];
         break;
      }
   }
}
//-->