function rnd(a,b) {
	return a + Math.floor(Math.random()*(b-a+1));
}

function freesissi() {
window.open('http://site.sourceoflight.net/popups/freesissi.html','freegift','width=335,height=350')
}

<!-- Begin
var how_many_ads = 4;
var now = new Date()
var sec = now.getSeconds()
var ad= rnd(1,4);


if (ad==1) {
txt="Once";
jscript="";
url="once-in-the-blue.html";
alt="Once (in the blue)";
banner="http://site.sourceoflight.net/banners/home/once.jpg";
width="421";
height="281";
}



if (ad==2) {
txt="Pensi Fan";
jscript="";
url="pensi.html";
alt="Pensi Fan";
banner="http://site.sourceoflight.net/banners/home/pensi.jpg";
width="421";
height="281";
}


if (ad==3) {
txt="PH Snowball";
jscript="";
url="snowball.html";
alt="PH Snowball";
banner="http://site.sourceoflight.net/banners/home/phsnowball.jpg";
width="421";
height="281";
}


if (ad==4) {
txt="TD Madison Pendant";
jscript="";
url="td-madison.html";
alt="TD Madison Pendant";
banner="http://site.sourceoflight.net/banners/home/td-madison.jpg";
width="421";
height="281";
}

if (ad==5) {
txt="Palm III by 3Com, in stock!";
jscript="";
url="td-lvpendants.html";
alt="2 thousand degrees pendants";
banner="http://site.sourceoflight.net/banners/home/td-pendants.jpg";
width="421";
height="281";
}


if (ad==6) {
txt="The World's Largest Online Bookstore, Amazon.com";
url="axolight.html";
jscript=""
alt="Featuring Clavius Suspension Lamps";
banner="http://site.sourceoflight.net/banners/home/clavius.jpg";
width="421";
height="281";
}


document.write('<a href=\"' + url + '\" onclick=\"' + jscript + '\">');
document.write('<img src=\"' + banner + '\" width=')
document.write(width + ' height=' + height + ' ');
document.write('alt=\"' + alt + '\" border=0>');
// End -->