Post after ajax call not set isn't set (using jQuery)

Question

I have this AJAX call:

$.ajax({
    url: '../php/functions/area_id_to_table_name.php',
    type: 'POST',
    dataType: 'json',
    scriptCharset: "utf-8",
    data: { areaOfWorkId: userAreaOfWorkArray }
}).always(nextStep);

function nextStep(a, textStatus, b) {
    if (textStatus === 'success') {
        // success
        alert(a);
    } else {
        // failure
        alert('Failed: ' + b);
    }
}

and this PHP code (the URL):

<?php
require_once 'connection.php';
$link = conenct('localhost', 'root', '', 'w_db');

mysql_query( "SET NAMES utf8" );
mysql_query( "SET CHARACTER SET utf8" );
mysql_set_charset('utf8', $link);

Class AreaInfo{
    public $areaName;
    public $areaId;
    public $areaTableName;
}
print_r($_POST['areaOfWorkId']);
$areaOfWorkArray = $_POST['areaOfWorkId'];

$areaInfoArray = Array();
foreach ($areaOfWorkArray as $key){
    $key = mysql_real_escape_string($key);
    if ($key == 0) continue;
    $tmpObj = new AreaInfo();
    $tmpObj->areaId = $key;
    $query = mysql_query("SELECT areaOfWork, tableName FROM area_of_work WHERE id = '$key'");
    $query = mysql_fetch_assoc($query);
    $tmpObj->areaName = $query['areaOfWork'];
    $tmpObj->areaTableName = $query['tableName'];
    array_push($areaInfoArray, $tmpObj);    
}

print_r($areaInfoArray);
echo json_encode($areaInfoArray);
?>

I am getting alert of this error:

Failed: SyntaxError: JSON.parse: unexpected character

On the Chrome developer tool it seems that all works fine. When I open the PHP page i see this lines:

Notice: Undefined index: areaOfWorkId in C:\\xampp\\htdocs\\job-skills\\php\\functions\\area_id_to_table_name.php on line 15

Notice: Undefined index: areaOfWorkId in C:\\xampp\\htdocs\\job-skills\\php\\functions\\area_id_to_table_name.php on line 16

Warning: Invalid argument supplied for foreach() in C:\\xampp\\htdocs\\job-skills\\php\\functions\\area_id_to_table_name.php on line 19

Answer 1

When you call print_r , you put garbage (I mean not JSON) in the response. The browser can't interpret it as JSON.