Add a perl script in the questionnaire using User Interface

Hello everyone,
I try to collect through the questionnaire certain ENVs (environment variables), namely the device name (PC name or Tablet name).
I using the SSi Web version 7.0.30.

I need to add computer-name ENV in the questionnaire a perl or javascript code.

I have find a solution to obtain some ENV, accessing from browser a demo.pl file with this script:

use strict;
print "ENV_PCNAME:$ENV{'ENV_PCNAME'}";

Now I need to add this perl code in the questionnaire using "SSI Web CAPI Module" user interface, but I don't know where.

Do you have any idea how I could do this?

PS. Also a javascript example to get ENV is very useful. :)

Thanks