use CGI;
my $q = CGI->new; # create a query object
my $f = $q->param("foo"); # get the foo field
or a function-oriented module:
use CGI qw(param); # import the param function
my $f = param("foo"); # get the foo field
If you don't want to spell out every possible
subfunction, bring them all in:
use CGI qw(:all); # define "param" and 800-gazillion others
my $f = param("foo");