jquery.ajax json wrong?

Question

hey i have a problem submitting my data via jquery and back:

$.ajax({
    url: "checkAvailability.php",
    type: 'POST',
    data : {data:JSON.stringify(data)},
    success: function(data) {
        if (data.result == 0) {
            alert("0")
        } 
        if(data.result == 1) {
            alert("1")
        }
    }
});

so, ONE of those if-conditions must be true, because of:

checkAvailability.php:

if(isset($_POST['data'])) {
    define('SECURE', true);
    include "storescripts/connect_to_mysql.php";

    require 'AvailabilityChecker.php';

$config = array(etc..);

    $availabilityChecker = new AvailabilityChecker($config);

    $data = $_POST['data'];
    $data = json_decode($data,true);

    preg_match( '/(\d+(\.\d+)?)/', $data['x'] , $m);
    $x =  $m[0];

    if($availabilityChecker->check_availability($x)) {
        echo json_encode(array("error" => "is ok", "result"=>1));
    } else {
        echo json_encode(array("error" => "not ok", "result"=>0));
    }
}

data.result have to be 1 OR 0. anybody can tell me why there is no alert-message? greetings!

UPDATE:

$.ajax({
    url: "checkAvailability.php",
    type: 'POST',
    data : {data:JSON.stringify(data)},
    success: function(data) {
        if (data.result == 0) {
            alert("0")
        } else { alert("fail-1") }
        if(data.result == 1) {
            alert("1")
        } else { alert("fail-2") }
    }
});

now i get first the fail-1 alert and than the fail-2 alert, so both if-conditions are false, why?

Answer 1

You need to specify the dataType, otherwise jquery will instead try to guess what you are trying to do. In this case it is incorrectly guessing text/html rather than application/json.

$.ajax({
    url: "checkAvailability.php",
    type: 'POST',
    dataType: 'json',
    data : {data:JSON.stringify(data)},
    success: function(data) {
        if (data.result == 0) {
            alert("0")
        } else { alert("fail-1") }
        if(data.result == 1) {
            alert("1")
        } else { alert("fail-2") }
    }
});

You should also properly set the content-type header in php, before you echo the json.

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

You can get away with doing either-or, but i'd suggest doing both.

Answer 2

a solution can be

success: function(d) {

        data = jQuery.parseJSON(d);

        if (data.result == 0) {
            alert("0")
        }
        if(data.result == 1) {
            alert("1")
        }
    }

this becouse $.ajax will no decode the result text from the page for you. what the php code is doin in fact is to print a json string to the stream.

Note that the the output passed to success can be any sort of text (also xml code on simply text)

Answer 3

You need to set the correct content type header in your php file:

header('Content-Type: application/json');
//snip
echo json_encode(array("error" => "is ok", "result"=>1));