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

use CGI qw( -nph ) ;

my $cgi = CGI->new;

if ( $cgi->param('logout') ) {
    print $cgi->header(
        -status => '401 Unauthorized',
        "WWW-Authenticate" => qq~Basic realm="foobar"~,
      ),
      $cgi->start_html,                                                       
      'Goodbye',                                                              
      $cgi->end_html,                                                         
    ;
}
else {
    print $cgi->header( 'text/html' ),
      $cgi->start_html(),
      $cgi->h1("Success"),
      $cgi->a({href=>"?logout=1"}, 'logout'),
      $cgi->end_html,
    ;
}