function displayad(){

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="Corporate Membership";
url="../corporate-membership.php";
alt="Corporate Membership";
banner="ads/corporate-membership.gif";
width="399";
height="60";
}
if (ad==2) {
txt="Register Today!";
url="../newemployer.php?place=us";
alt="Register Today!";
banner="ads/employer-register.gif";
width="399";
height="60";
}
if (ad==3) {
txt="Register Today!";
url="../newjobseeker.php?place=us";
alt="Register Today!";
banner="ads/jobseeker-register.gif";
width="399";
height="60";
}
document.write('<center>');
document.write('<a href=\"' + url + '\" target=\"_top\">');
document.write('<img src=\"' + banner + '\" width=')
document.write(width + ' height=' + height + ' ');
document.write('alt=\"' + alt + '\" border=0></a>');
document.write('</center>');

}