How to parse error and status message from serialize()?

I have this code

$(document).ready(function(){

    //  ...

    $('form').submit(function() {

    // ...

    $.ajax({
        type: "GET",
        url: "/cgi-bin/ajax.pl",
        contentType: "application/json; charset=utf-8",
        dataType: "json",

        data: $(this).serialize(),

        error: function(XMLHttpRequest, textStatus, errorThrown) { 
        $('div#create_result').text(
            "responseText: " + XMLHttpRequest.responseText +
            ", textStatus: " + textStatus +
            ", errorThrown: " + errorThrown);


        $('div#create_result').addClass("error");
        }, // error 

        success: function(result){
        if (result.error) { // script returned error
            $('div#create_result').text("result.error: " + result.error);
            $('div#create_result').addClass("error");
        } // if
        else { // perl script says everything is okay
            $('div#create_result').text(
            "result.success: " + result.success +
            ", result.userid: " + result.userid);
            $('div#create_result').addClass("success");
        } //else
        } // success
    }); // ajax

    $('div#create_result').fadeIn();
    return false;

    });
});

which always gives error messages, if it was successful.

Example:

responseText: Content-Type: application/json; charset=utf-8 {"success" : "Activity created", "Activity number" : "38"}, textStatus: par开发者_如何学JAVAsererror, errorThrown: SyntaxError: JSON.parse

Any ideas what is wrong?

Update:

Here is how I make the JSON strings in the server-side Perl script.

...
$json = qq{{"error" : "Owner $owner doesn't exist"}};

...
$json = qq{{"success" : "Activity created", "Activity number" : "$id"}};
...

print $cgi->header(-type => "application/json", -charset => "utf-8");
print $json;

This:

parseError,
SyntaxError: JSON.parse

Your response JSON is not acceptable to the parser, it might be malformed. Your posted responseText has headers in it, those should NOT be present.:

Content-Type: application/json; charset=utf-8 {"success" : "Activity created", "Activity number" : "38"}

Consider using Perl's JSON module, which handles serialization and parsing for you. There is an XS backend (for speed), as well as a PP (Pure Perl) backend.