#!/usr/bin/perl 
use strict; 
use warnings FATAL => qw/all/; 
use CGI; 
use CGI::Carp qw/fatalsToBrowser/; 
 
##### 
 
my $templates = { A => 'This is template A', 
                  B => 'This is template B', 
                  C => 'This is template C' }; 
 
my $default_template = 'A'; 
 
my $cgi = CGI->new( ); 
 
my $template_content = $templates->{ $cgi->param('template') // $default_template } // $templates->{ $default_template }; 
 
##### 
 
print $cgi->header( ); 
 
print $cgi->start_html( ); 
 
print $cgi->start_form( ); 
 
print $cgi->popup_menu( -name     => 'template', 
                        -values   => [ sort keys %$templates ], 
                        -default  => $default_template, 
                        -onChange => "window.location='?template='+this.value" ); 
 
print q{<noscript>} . $cgi->submit( -value => 'Update' ) . q{</noscript>}; 
 
print q{<br />} . $cgi->textarea( -name     => 'template_content', 
                                  -default  => $template_content, 
                                  -override => 1, # required otherwise default when script first invoked is used (sticky). 
                                  -rows     => 10, 
                                  -columns  => 100 ); 
 
print $cgi->end_form( ); 
 
print $cgi->end_html( ); 
 
##### 
 
exit( );