If you use the CGI.pm shortcuts, you can just dump a hidden field with an arrayref for a value, and it'll show up as a multivalue field on reply:

param("basket", 1..10);
...
print hidden("basket");
[download]

and in response you'll get:

my @list = param("basket"); # @list = (1..10);
[download]

-- Randal L. Schwartz, Perl hacker