#!/usr/bin/perl
use strict;
use warnings;

use Tk;
use Tk::NoteBook;

my $main = MainWindow->new();
my $note = $main->NoteBook()->pack();
my $text = '';

my $page1 = $note->add('Notebook-1', -label => 'ReiterEins');
my $page2 = $note->add('Notebook-2', -label => 'ReiterZwei', -raisecmd => \&test);

my $entry = $page1->Entry()->pack();
$page2->Label(-textvariable => \$text)->pack();

$entry->focus();

MainLoop();

sub test {
    $text = $entry->get();
    $entry->delete('0.0','end');
}