#!/usr/bin/perl -w
 use lib qw(lib);
 use HTML::Menu::TreeView;
 use CGI;
 use strict;
 my @tree = (
     {
      onclick => "alert('onclick');",
      text    => 'onclick',
     },
     {
      text  => 'Html::Menu::TreeView',
      href  => "./open.pl?open=1",
      empty => 1,                        # this is the important line
     }
 );
 my $TreeView = new HTML::Menu::TreeView();
 my $q        = new CGI;
 if ($q->param('open')){
 $tree[1]{subtree} = [
                      {
                       text    => 'Examples',
                       subtree => [
                                   {
                                    text => 'FO Syntax',
                                    href => './fo.pl',
                                   },
                       ],
                      },
   ];
 undef $tree[1]{empty};
 
 }
 print($q->header
         . $q->start_html(
                          -title  => 'OO',
                          -script => $TreeView->jscript() . $TreeView->preload(),
                          -style  => {-code => $TreeView->css()}
         )
         . $TreeView->Tree(\@tree)
         . $q->end_html
 );