0 values entered in form not recognised by CGI

[idonalds]

This is a little odd, but persistent. I have set up a HTML form and CGI to receive numerical values from the form. However, if I enter '0' the CGI thinks a value has not been entered. To enter zero I need to put '00'

Has anyone encountered this?

Thanks!

[chrisranjana]

How you are validating that form field in perl ?

[robertketter]

0 (ZERO) is false in perl. So if you are checking $field and its value is 0, it is false and therefore has no value.

[idonalds]

Thanks for the replies!

The CGI takes in the HTML variable as shown here:
$hold_distance_up = $query->param('distance_up');
$hold_distance_up is expected to be a number between 0 and 100000. However, 0 is seen as a NULL value, so Perl objects to this. But, I have seen other people sites accept 0 as a value and work perfectly well.

Thanks again.

[robertketter]

here try this...


$hold_distance_up = $query->param('distance_up');
if (!$hold_distance_up){ $hold_distance_up == 0;}
:)

[Charles]

here try this...


$hold_distance_up = $query->param('distance_up');
if (!$hold_distance_up){ $hold_distance_up == 0;}
:)Please, this is PERL and so that can be shortened to:$hold_distance_up = $query->param('distance_up') || 0;

[idonalds]

Thanks again,

I can now use 0 in my web form. The problem I think is that I was using these variables in an AND comparison in my Perl CGI.

0 is actually sent to the CGI though.

Still confused, but it works.