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("<IMG SRC='" + img_source + "' WIDTH=100% HEIGHT=192 BORDER=0 ALT='" + alt + "'>");
}
banner.prototype.display = display;
banners = new Array();
banners[0] = new banner("http://schumacher.kepno.pl/upload/1.jpg",
                        "http://www.sdres_strony1 target='_blank'",
                        "heder 1",
                        2);
banners[1] = new banner("http://schumacher.kepno.pl/upload/2.jpg",
                        "http://www.adres_strony2 target='_blank'",
                        "heder 2",
                        1);
banners[2] = new banner("http://schumacher.kepno.pl/upload/3.jpg",
                        "http://www.adres_strony3 target='_blank'",
                        "heder 3",
                        3);
banners[3] = new banner("http://schumacher.kepno.pl/upload/4.jpg",
                        "http://www.sdres_strony1 target='_blank'",
                        "heder 1",
                        2);
banners[4] = new banner("http://schumacher.kepno.pl/upload/5.jpg",
                        "http://www.adres_strony2 target='_blank'",
                        "heder 2",
                        1);
banners[5] = new banner("http://schumacher.kepno.pl/upload/6.jpg",
                        "http://www.adres_strony3 target='_blank'",
                        "heder 3",
                        3);
banners[6] = new banner("http://schumacher.kepno.pl/upload/7.jpg",
                        "http://www.sdres_strony1 target='_blank'",
                        "heder 1",
                        2);
banners[7] = new banner("http://schumacher.kepno.pl/upload/8.jpg",
                        "http://www.adres_strony2 target='_blank'",
                        "heder 2",
                        1);
banners[8] = new banner("http://schumacher.kepno.pl/upload/9.jpg",
                        "http://www.adres_strony3 target='_blank'",
                        "heder 3",
                        3);
banners[9] = new banner("http://schumacher.kepno.pl/upload/10.jpg",
                        "http://www.sdres_strony1 target='_blank'",
                        "heder 1",
                        2);
banners[10] = new banner("http://schumacher.kepno.pl/upload/11.jpg",
                        "http://www.adres_strony2 target='_blank'",
                        "heder 2",
                        1);
					
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("<IMG SRC='" + banners[i].img_source + "' WIDTH=100% HEIGHT=192 BORDER=0 ALT='" + banners[i].alt + "'>");
         return banners[i];
         break;
      }
   }
}