
<!--
<!-- Original:  Rich Galichon (rich@galichon.net) -->
<!-- Web Site:  http://www.galichon.net -->

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
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 + "' WIDTH=468 HEIGHT=60 BORDER=0 ALT='" + alt + "'></A>");
}
banner.prototype.dispBanner = dispBanner;
banners = new Array();
banners[0] = new banner("/AdvertGifs/apress20.gif",
                        "/apress.htm",
                        "Apress",
                        20);
banners[1] = new banner("/AdvertGifs/msp20.gif",
                        "/catalog/search.asp?publisher=microsoft%20press",
                        "Microsoft Press",
                        20);
banners[2] = new banner("/AdvertGifs/thomson20.gif",
                        "/getanimated.htm",
                        "Thomson",
                        10);
banners[3] = new banner("/AdvertGifs/cs2.gif",
                        "/cs2.htm",
                        "Adobe Press, New Riders, Peachpit Press, Sams",
                        20);
banners[4] = new banner("/AdvertGifs/dummies20.gif",
                       "/catalog/search.asp?title=photoshop&contents=dummies&publisher=wiley",
                        "Wiley",
                        20);
banners[5] = new banner("/AdvertGifs/bestsellers20.gif",
                        "/catalog/search.asp?publisher=gsp",
                        "GSP",
                        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 + "' WIDTH=468 HEIGHT=60 BORDER=0 ALT='" + banners[i].alt + "'></A>");
return banners[i];
break;
      }
   }
}
//  End -->
