function banner(imgSource,url,alt,chance) {
this.imgSource = imgSource;
this.url = url;
this.alt = alt;
this.chance = chance;
}
function dispBanner() {
with (this) document.write("<IMG SRC='" + imgSource + "' ALT='" + alt + "'></A>");
}
banner.prototype.dispBanner = dispBanner;
banners = new Array();
banners[0] = new banner("images/construction1.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);

banners[1] = new banner("images/construction2.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);

banners[2] = new banner("images/construction3.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);

banners[3] = new banner("images/construction4.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);

banners[4] = new banner("images/construction5.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);

banners[5] = new banner("images/construction6.jpg",
                        "",
                        "Welcome to SEARCHforacontractor.com",
                        16);




///////////////////////////////////////////////////
// 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("<IMG SRC='" + banners[i].imgSource + "' ALT='" + banners[i].alt + "'></A>");
return banners[i];
break;
      }
   }
}