if ($Salesperson eq "") {
     print "Location:
     http://localhost/cgi-bin/c12ex3b.html\n\n";
}

if ($Sales == "") {
      print "Location:
     http://localhost/cgi-bin/c12ex3b.html\n\n";
}

if ($Rate == "") {
      print "Location:
     http://localhost/cgi-bin/c12ex3b.html\n\n";
}