use strict;
use warnings;
use CGI;
my $CGI_obj = CGI->new;
my $email = $CGI_obj->param('email'); # or is it params?
if ($email =~ m/.*?@.*?\..*?/) {
  print "This e-mail is valid\n";
}
else {
  print "This is not a valid e-mail\n";
}