Dear Monks

I'm fairly new to perl CGI, and am trying to write a simple cgi based calendar. I've run into a problem trying to update the value of a hidden field in a self-referring url. Here's a minimal example:

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;
use CGI;
use CGI::Carp qw(fatalsToBrowser);

my $q = new CGI;
print $q->header; 
print $q->start_html;
my $serverRoot = "$ENV{SERVER_NAME}";

my $previousTotal = $q->param('sumTotal');

print $q -> h2("Previous Total: $previousTotal<br>");

my $currentTotal = $previousTotal + 2;

print $q -> h2("Current Total: $currentTotal<br>");

print $q -> start_form(
                -name    => 'addition',
                -method  => 'GET',
                -enctype => &CGI::URL_ENCODED,
                -action => "http://$serverRoot/cgi-bin/sum.cgi" # <-se
+lf url;
            );

print $q -> hidden(
                -name => 'sumTotal', 
                -value => "$currentTotal"
             );

print $q->submit(
            -name => 'button',
            -value => 'Add 2',
            );

print $q ->end_form;
print $q ->end_html;

[download]

I thought that each time the button is pressed, the value of $currentTotal should increase by 2. After pressing the button once, $currentTotal increases to 4, but when the button is pressed again, -sumTotal is still set to 2 in the url, and not 4 as I expected.

If anyone could explain why, or direct me towards an answer, I'd be very grateful!

Thanks in advance

Michael

In reply to perl CGI: updating hidden field values for self-referring url by mtmcc

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