var how_many_ads = 4;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;

if (ad==1) {
txt="";
alt="";
banner="images/home_main_1.jpg";
width="766";
height="246";
}

if (ad==2) {
txt="";
alt="";
banner="images/home_main_2.jpg";
width="766";
height="246";
}

if (ad==3) {
txt="";
alt="";
banner="images/home_main_3.jpg";
width="766";
height="246";
}

if (ad==4) {
txt="";
alt="";
banner="images/home_main_4.jpg";
width="766";
height="246";
}

document.write('<img src=\"' + banner + '\" width=');
document.write(width + ' height=' + height + ' ');
document.write('alt=\"' + alt + '\" border=0>');

// End -->