Problem with CGI.pm generated forms

MrNobo1024 has asked for the wisdom of the Perl Monks concerning the following question:

Here is the code:

#!perl -Tw
use CGI qw(:standard);
use strict;
my $num = param('number') || 0;
print header, start_html;
print "Your number is $num.";
print start_form;
print hidden('number', $num + 1);
print submit('Get next number');
print end_form;
print end_html;
[download]

The first time this is run, it prints "Your number is 0" and the hidden field is set to 1, as expected. But when I click on the button and it calls count.cgi?number=1, it prints "Your number is 1" but the hidden field is again set to 1! Why isn't it going to 2?

--MrNobo1024
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Comment on Problem with CGI.pm generated forms Download Code

Replies are listed 'Best First'.
Re: Problem with CGI.pm generated forms by Hero Zzyzzx (Curate) on Aug 14, 2002 at 01:21 UTC
Mayhap you should check out the "-override" option? By default, form values are sticky, and you need to set them explicitly how jeffa did above, or by passing them to your method and setting "-override" to a true value. `#!/usr/bin/perl + use CGI qw(:standard); use strict; my $num = param('number') \|\| 0; print header, start_html; print "Your number is $num."; print start_form; print hidden(-name=>'number', -value=>$num + 1,-override=>1); print submit('Get next number'); print end_form; print end_html;` [download] -Any sufficiently advanced technology is indistinguishable from doubletalk.	[reply] [d/l]
(jeffa) Re: Problem with CGI.pm generated forms by jeffa (Bishop) on Aug 14, 2002 at 01:16 UTC
Very common pitfall ... you need to also set the value with the param() method: `param('number',$num + 1); print hidden('number', $num + 1);` [download] I can't remember why off hand though ... UPDATE: LOL - you think i would have known that from the advice i gave at (jeffa) Re: Unstickying CGI ... Hero Zzyzzx++ jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l]