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

if($params{neu}){
  print $cgi->redirect(-url => '/index.html');
}
else{
  print $cgi->header(-type => 'text/html');
  do_the_rest();
}

exit;

sub do_the_rest{
  print $cgi->start_form(),
        $cgi->submit(-name => "neu", -value => "Neu"),
        $cgi->end_form();
}