my $q = CGI->new();
my $domain = $q->param('domain');

my $result = `ping $domain`;

##</code><code>##

my $domain='';
$q->param('domain') =~ /^([a-zA-Z0-9\.]+)$/
    and $domain = $1;

##</code><code>##

$q->param('domain') =~ /^(.+)$/
    and $domain = $1;