var how_many_ads = 3;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;
if (ad==1) {
txt="Serveis on-line";
url="servicios/servicios.htm";
alt="Serveis on-line";
banner="images/banner_c.gif";
width="350";
height="60";
}
if (ad==2) {
txt="Serveis on-line";
url="servicios/servicios.htm";
alt="Serveis on-line";
banner="images/banner_c2.gif";
width="350";
height="60";
}
if (ad==3) {
txt="Serveis on-line";
url="servicios/servicios.htm";
alt="Serveis on-line";
banner="images/banner_c3.gif";
width="350";
height="60";
}

document.write('<center>');
document.write('<a href=\"' + url + '\" target=\"_self\">');
document.write('<img src=\"' + banner + '\" width=')
document.write(width + ' height=' + height + ' ');
document.write('alt=\"' + alt + '\" border=1><br>');
document.write('</center>');