function banner(imgSource,url,alt,chance) {
this.imgSource = imgSource;
this.url = url;
this.alt = alt;
this.chance = chance;
}
function dispBanner() {
with (this) document.write("<A HREF=" + url + "><IMG SRC='" + imgSource + "' BORDER=0 ALT='" + alt + "'></A>");
}
banner.prototype.dispBanner = dispBanner;
banners = new Array();
banners[0] = new banner("http://www.frmagazine.it/collaborazione/banner/frmscrivipernoi.gif",
                        "http://www.frmagazine.it/collaborazione",
                        "Entra nella redazione",
                        20);
banners[1] = new banner("http://www.frmagazine.it/collaborazione/sponsor/simerecologicabanner.jpg",
                        "http://www.simerecologica.it target='_blank'",
                        "SIMER srl Frosinone, raccolta, separazione, stoccaggio, smaltimento e trattamento di rifiuti speciali non pericolosi, solidi e liquidi",
                        20);
banners[2] = new banner("http://www.frmagazine.it/collaborazione/banner/comeunclick.jpg",
                        "http://www.frmagazine.it/collaborazione",
                        "Diventa sponsor: semplice ed economico",
                        10);
banners[3] = new banner("http://www.frmagazine.it/collaborazione/sponsor/lallobaby/pannolino1.jpg",
                        "http://www.frmagazine.it/collaborazione/sponsor/lallobaby/ target='_blank'",
                        "Lallo Baby Pannolini. Spaccio aziendale vendita offerta Frosinone Latina Roma",
                        10);
banners[4] = new banner("http://www.frmagazine.it/collaborazione/sponsor/lallobaby/pannolino2.jpg",
                        "http://www.frmagazine.it/collaborazione/sponsor/lallobaby/ target='_blank'",
                        "Lallo Baby Pannolini. Spaccio aziendale vendita offerta Frosinone Latina Roma",
                        10);
banners[5] = new banner("http://www.frmagazine.it/collaborazione/sponsor/lallobaby/pannolino3.jpg",
                        "http://www.frmagazine.it/collaborazione/sponsor/lallobaby/ target='_blank'",
                        "Lallo Baby Pannolini. Spaccio aziendale vendita offerta Frosinone Latina Roma",
                        10);                                                
banners[6] = new banner("http://www.frmagazine.it/collaborazione/sponsor/aranova/aranova468x60.jpg",
                        "http://www.frmagazine.it/collaborazione/sponsor/aranova/ target='_blank'",
                        "Portici gazebi coperture in legno massello e lamellare",
                        20);


                        
                        
                        
///////////////////////////////////////////////////
// banners[x] = new banner(<banner source image>,                                           //                         <url to link to when the banner is clicked>,                     //                         <alt>                                                            //                         <the chance this banner has in which to be randomly selected>);
// To increase the chance of a banner being randomly selected, increase it's corresponding  // 'chance' property relative to the other banners.
///////////////////////////////////////////////////
sum_of_all_chances = 0;
for (i = 0; i < banners.length; i++) {
sum_of_all_chances += banners[i].chance;
}
function randomBanner() {
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].imgSource + "' BORDER=0 ALT='" + banners[i].alt + "'></A>");
return banners[i];
break;
      }
   }
}