Setting $CGI::POST_MAX to 100 may be the reason why the parameter is not set with four or more check boxes checked. From CGI:
$CGI::POST_MAX
If set to a non-negative integer, this variable puts a ceiling on the size of POSTings, in bytes. If CGI.pm detects a POST that is greater than the ceiling, it will immediately exit with an error message. This value will affect both ordinary POSTs and multipart POSTs, meaning that it limits the maximum size of file uploads as well. You should set this to a reasonably high value, such as 1 megabyte.
...
An attempt to send a POST larger than $POST_MAX bytes will cause *param()* to return an empty CGI parameter list. You can test for this event by checking *cgi_error()*, either after you create the CGI object or, if you are using the function-oriented interface, call <param()> for the first time. If the POST was intercepted, then cgi_error() will return the message "413 POST too large".

In reply to Re: checkbox_group CGI.pm madness by eieio
in thread checkbox_group CGI.pm madness by Discipulus

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