use CGI;
my $q = new CGI;
my $missed;
my @required = qw(name address phone email);
for (@required) {
$missed .= "
$_\n" if $q->param($_) eq "";
}
do {
print "Content-type: text/html\n\n";
print qq~
You forgot to fill in the following required fields:
~;
} if $missed;