#!/usr/bin/env perl

use JSON::XS;
use Data::Dumper;
use strict;
use warnings;

my %hash = ( cl_ip => 209890 );

print Dumper( \%hash );

print qq(\n);

my $json = encode_json \%hash;

print qq($json\n\n);

#------------------------------

$hash{cl_ip} += 0;

print Dumper( \%hash );

print qq(\n);

$json = encode_json \%hash;

print qq($json\n\n);

#------------------------------

$hash{cl_ip} = "209890";

print Dumper( \%hash );

print qq(\n);

$hash{cl_ip} += 0;

print Dumper( \%hash );

print qq(\n);

$json = encode_json \%hash;

print qq($json\n\n);

__END__

karl-mac-mini:monks karl$ ./json.pl 
$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}

$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}

$VAR1 = {
          'cl_ip' => '209890'
};

$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}