var banners = new Array();
banners[0] = new Banner("img/foto_home1.jpg");
banners[1] = new Banner("img/foto_home2.jpg");
banners[2] = new Banner("img/foto_home3.jpg");

function Banner(image) {
	this.image = image;
    return this;
}
var bNum = Math.round(Math.random() * (banners.length - 1));

document.write("<img src=\"" + banners[bNum].image + "\" border=\"0\">");