## LoginForm.pm
package LoginForm;

use strict;
use base qw(Tk::Frame);
Tk::Widget->Construct('LoginForm');

sub Populate 
{
   my ($cw, $args) = @_;
   $cw->SUPER::Populate($args);

   my $f = $cw->Frame->pack;
   my $msg = $f->Label->
      grid(qw/-columnspan 2 -sticky ew/);

   my $userE = $f->Entry;
   $f->Label(-text => "User:")->
      grid($userE, -sticky => 'e');

   my $passE = $f->Entry(-show => '*');
   $f->Label(-text => "Password:")->
      grid($passE, -sticky => 'e');   

   my $button = $f->Button(
      -text => 'Login',
      -command => [Login => $cw]
   )->grid(qw/-columnspan 2 -pady 4/);

   $cw->Advertise(Message     => $msg);
   $cw->Advertise(UserEntry   => $userE);
   $cw->Advertise(PassEntry   => $passE);
   $cw->Advertise(LoginButton => $button);
} 

sub Login 
{
   my $cw = shift;
   my $user = $cw->Subwidget('UserEntry')->get;
   my $pass = $cw->Subwidget('PassEntry')->get;
   print "$user/$pass\n";
}
1;
  
## login.pl
use Tk;
use LoginForm;

my $mw = MainWindow->new;
$mw->LoginForm->pack;

MainLoop;