Hi Monks,

I'm getting strange results from a subroutine that is passed a hash of values, one of which comes from a checkbox from an online form.

The relevant html and code are as follows:

# html
# Note that if the user selects the checkbox, the value is 'on'
<tr><td>I'm logging in from home</td><td><input type="checkbox" name="
+place"></td></tr>

# cgi
use strict;
use CGI qw(:cgi);
use Data::Dumper;
my $place = seewhatsthere(
  data     => param('place'),
  field    => 'Place',
);

sub seewhatsthere {
  my %hash = @_;
  html_start();
  print Dumper(%hash);
  exit(0);
}

[download]
What happens is this:

CASE 1: The checkbox is unchecked

# Dumped
$VAR1 = 'Place'; $VAR2 = undef; $VAR3 = 'data'; $VAR4 = 'field';

[download]
So we get

Place => undef
data => 'field'

which is strange and perhaps incorrect because I was expecting the following

data => undef
field => 'Place'

CASE 2: The checkbox is checked

# Dumped
$VAR1 = 'data'; $VAR2 = 'on'; $VAR3 = 'field'; $VAR4 = 'Place';

[download]
So we get

data => 'on'
field => 'Place'

which is correct.

My question is: When the checkbox is unchecked ( i.e. CASE 1 ), why do I get the strange results? Can someone shed some light on what's going on?

Thanks :)

update

Thanks to everybody for the wonderful solutions :)

In reply to Strange behaviour - cgi related by kiat

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