Another asumption: The object that is in $q is an object created by one of the many CGI modules that exist. A well known one that I have used is CGI.pm by Lincoln Stein. http://stein.cshl.org/WWW/software/CGI/

The syntax that is used as well as the name of the method "param" suggest it is CGI.pm.

This method returns several items of in about the parameters submitted from a form including its values. Depending on how the object is created all of the parameters that are submitted will have values.