Question

Am receiving null from json post using jquery. see my code below in order.

user fills in this form and submits:

<form name="newsletterSignup" id="newsletterSignup" method="post">

        <input type="text" name="firstName" id="firstName" type="text" autocomplete="off" placeholder="Enter your name" />

        <input type="text" name="email" id="email" type="text" autocomplete="off" placeholder="Enter a valid email address"/>

        <input type="submit" name="newsletterSubscribe" id="newsletterSubscribe" value="Sign me up now!" /> 

    </form>

Then this is run:

var BASE_URL = 'http://www.thegurucoder.com/';

$('#newsletterSignup').submit(function()
{

    var ajaxURL = BASE_URL + '_php/ajax/newsletterSubscribe.php';

    $.ajax({
        type: 'POST',
        url: ajaxURL,
        data: { firstName:$('#newsletterSignup #firstName').val(), email:$('#newsletterSignup #email').val()},
        dataType: 'json',
        success: function(data){

            alert(data);

            if(data.redirect == 'true')
            {

                window.location = data.url;

            }
            else
            {

                $(this).notify({prependTo:'#master', type:'negative', message:data.message, delay:3200, animation:'slide'});

            }

        }
    });

    return false;

});

Which in turn runs this:

function newsletterSubscribe()

{

if(isset($_POST['newsletterSubscribe']))
{

    header('Content-Type: application/json');

    $db = new Connection(DB_HOST, DB_USER, DB_PASS, DB_NAME);

    $firstName = $_POST['firstName'];
    $email = $_POST['email'];

    if($email != '')
    {

        if(isDuplicateValue('subscribers', 'email', $email))
        {

            echo json_encode(array(
                'message' => 'You have already subscribed to this newsletter.',
                'redirect' => 'false'
            ));

        }
        else
        {

            $parameters = array(
                'table' => 'subscribers',
                    'fieldsAndValues' => array(
                    'firstName' => $firstName,
                    'email' => $email,
                    'addedDate' => datetime()
                    )
            );

            $db->insert($parameters);

            echo json_encode(array(
                'redirect' => 'true',
                'url' => BASE_URL.'subscribed'
            ));

        }

    }
    else
    {

        echo json_encode(array(
            'message' => 'You did not enter a valid email address.',
            'redirect' => 'false'
        ));

    }

}

}

And the problem is:

Uncaught TypeError: Cannot read property ‘redirect’ of null

These are the headers i am getting in inspector.

Request URL:http://www.thegurucoder.com/_php/ajax/newsletterSubscribe.php
Request Method:POST
Status Code:200 OK
Request Headersview source
Accept:application/json, text/javascript, */*; q=0.01
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Content-Length:17
Content-Type:application/x-www-form-urlencoded
Cookie:PHPSESSID=f3015d3c6fa08e53fc562477da0f563f
Host:www.thegurucoder.com
Origin:http://www.thegurucoder.com
Referer:http://www.thegurucoder.com/blog
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7
X-Requested-With:XMLHttpRequest
Form Dataview URL encoded
firstName:
email:
Response Headersview source
Cache-Control:no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection:close
Content-Encoding:gzip
Content-Language:en-UK
Content-Length:20
Content-Type:text/html; charset=UTF-8
Date:Thu, 05 Jan 2012 15:21:54 GMT
Expires:Thu, 19 Nov 1981 08:52:00 GMT
Pragma:no-cache
Server:Apache/2.2.16 (Unix) mod_ssl/2.2.16 OpenSSL/0.9.8e-fips-rhel5 mod_bwlimited/1.4
Vary:Accept-Encoding
X-Powered-By:PHP/5.2.14

Answer 1

The problem with your code is that you are not posting ‘newsletterSubscribe’ field to your php file in ajax request but on that php file you are checking for ‘newsletterSubscribe’ in if condition as if(isset($_POST[‘newsletterSubscribe’])) .

So in php code change if(isset($_POST['newsletterSubscribe'])) to if(isset($_POST['firstName'])) and it will work for sure.