You seem to be confusing the send and return aspects. You are not sending JSON to the script as the serialize() method serializes a form's data into a query string, not JSON (this string can be decoded using the normal CGI methods). On the other hand, you are telling jQuery that your response will be JSON ( dataType: "json" in your javascript and $q->header("application/json") in your perl script) but you are not sending JSON back, just a plain string.

I don't know your exact requirements but I suspect you don't need to send JSON to your script, you may however need to return JSON. This may help you to see the difference:

Javascript

<script type="text/javascript" >
$(function() {
    $(".submit").click(function() {
        var formData = $("#reply-form").serialize();
        alert(formData);
    
        $.ajax({
            type: "post",
            url: "code.pl",
            cache: false,
            data: formData,
            dataType: "json",
            success: function(data) //onSuccess,
            {
                alert(data.calling_params);
            },
            error: function()
            {
                alert( "Sorry, there was a problem!" );
            }
        });
        return false;
    });
});
</script>

[download]

Perl

use strict;
use warnings;

use CGI;
use JSON;
use Data::Dumper;

my $q = new CGI;
my $in = $q->Vars;
my $string = Dumper ($in);
my $response = encode_json( { calling_params => "$string" } );

print $q->header("application/json");
print $response;

[download]

In reply to Re: Read JSON data from a form by tangent
in thread Read JSON data from a form by Anonymous Monk

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