foreach $name ( $obj->param )
{
   if ( undef ( $name ) )
  {
   # gehe wieder zur Eingabemaske
   }
}
else
{
my $vorname      = $obj->param ( "vorname"  );    #0
my $nachname     = $obj->param ( "nachname" );    #1
my $strasse      = $obj->param ( "strasse" );     #2
my $plz          = $obj->param ( "plz" );         #3
my $wohnort      = $obj->param ( "wohnort" );     #4
my $email        = $obj->param ( "email" );       #5
my $kontonummer  = $obj->param ( "kontonummer" ); #6
my $blz          = $obj->param ( "blz" );         #7
my $bankname     = $obj->param ( "bankname" );    #8
my $username     = $obj->param ( "username" );    #9
my $passwort     = $obj->param ( "passwort" );    #A
}

my $cgi = CGI->new();
my %params = $cgi->Vars();

my $errorMessages = "";
foreach my $key (qw(numeric integer id)) {
  if ($params{$_} =~ /\D/) {
    $errorMessages .= "Error: $key contains chars that are not numeric<br />";
  } # if
} # foreach

foreach my $key (qw(string1 string2 text)) {
  if ($params{$_} =~ /[^a-zA-Z0-9 ]/) {
    $errorMessages .= "Error: field $_ contains other characters than letters, numbers or spaces<br />";
  } # if
}  # foreach

if ($errorMessages) {
  &PrintError($errorMessages);
  exit;
}