...
$("#send").click(function(){
    
    $.ajax({
	     type: 'POST',
	     url: 'process.pl?first=<TMPL_VAR NAME="FR">&last=<TMPL_VAR NAME="LA">',
	     dataType: "json",
	     success: function(data) {

	       if(data){
	         alert("We pass!");
	       }
	     },
	     error: function() {
	       alert("We have a problem!");
	     }
	 });
  });
...

##</code><code>##

#!/usr/bin/perl  

use strict;
use warnings;

use CGI;

my $q = new CGI;
my $first = $q->param("first");
my $last = $q->param("last");

print "F=$first - L=$last\n";

exit;

##</code><code>##

...
url: 'process.pl?<TMPL_VAR NAME="FR"> <TMPL_VAR NAME="LA">',
...

##</code><code>##

...
my ($first, $last ) = @ARGV;
print "F=$first - L=$last\n";
...