i finally got to run the serverpost element of XUL (this uses the XMLhttpRequest)
turns out, i got mixed up with the serverpostname attribute from the element (where i will get the values from) and used name instead of the id attribute for the serverpost element..
here's the perl generated XUL code

<http:serverpost
   id="foo" #i used 'name' before... that did not work.
   targetURL="/cgi-bin/logger.pl"
   onHTTPResponseReceived="alert('this.responseText;')"
/>
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and used the CGI

#!/usr/bin/perl -w
use CGI;
#CGI stuff
my $q = new CGI;
my %f; #($f) should be declared as a hash

foreach my $i ($q->param()) {
$f{$i} = $q->param($i);
}
my $empid = $q->param('empid');
my $code = $q->param('code');

#sql things follow...
[download]

thanks everyone for the enlightenment~