Retrieving POST Data from AJAX Call to PHP - php

Question

Three days had passed and still having problems to get this things work.
This AJAX Call on my js file seems working when it comes to sending JSON data:
var _lname = $('#ptLastName').val();
var _fname = $('#ptFirstName').val();
var _mname = $('#ptMiddleName').val();
var _gender = $('#ptGender').val();
var _bday = $('input[name="birthdate"]').val(); // $('#ptBirthDate').val();
var _ssn = $('#ptSSN').val();
$.ajax({
type: "POST",
url: ".././CheckPerson.php",
data: "{'lastName':'" + _lname + "','firstName':'" + _fname + "','middleName':'" + _mname + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
var res = response.d;
if (res == true) {
jAlert('Person Name already exists!', 'Error');
return;
}
})
but in my PHP file:
$lastname = json_decode($_POST['lastName']);
$firstname = json_decode($_POST['firstName']);
$middlename = json_decode($_POST['middleName']);
$response = array();
mysql_connect ("*****", "****") or die ('Error: ' . mysql_error());
mysql_select_db ("********");
$query = "SELECT Lastname, Firstname, MiddleName FROM tbl_people WHERE Lastname = '$lastname' || Firstname = '$firstname' || MiddleName = '$middlename'";
$result = mysql_query($query);
$row = mysql_fetch_array($result);
if ($row) {
$response = json_encode(array('d' => true, 'test' => $lastname));
}
else {
$response = json_encode(array('d' => false, 'test' => $lastname));
}
echo $response;
print json_encode($_POST);
some error from firebug console says:
<br />
<b>Notice</b>: Undefined index: lastName in <b>C:\xampp\htdocs\..\CheckPerson.php</b> on line <b>2</b><br />
<br />
<b>Notice</b>: Undefined index: firstName in <b>C:\xampp\htdocs\..\CheckPerson.php</b> on line <b>3</b><br />
<br />
<b>Notice</b>: Undefined index: middleName in <b>C:\xampp\htdocs\..\CheckPerson.php</b> on line <b>4</b><br />
{"d":false,"test":null}[]
i believe that json_decode() is working fine in my php file but $_POST[''] can't recognize my posted data from my ajax call w/c variables had been declared:
data: "{'lastName':'" + _lname + "','firstName':'" + _fname + "','middleName':'" + _mname + "'}",
I believe I am doing right with my codes seems i had read many questions here and done what they had said but don't know why the error occurred.
Is there any problem/bug you had seen? please tell me.

Answer 1

Can you see the ajax request data using the firebug console?
You cannot get the lastname, firstname from $_POST. It's inside the json string. First, you have to get the data using
$data = $_POST['data'] or $_REQUEST['data']
Then, decode the $data using json_decode() and access your attributes.
json_decode($data);

Answer 2

$post = file_get_contents('php://input');

Answer 3

instead of this
data: "{'lastName':'" + _lname + "','firstName':'" + _fname +
"','middleName':'" + _mname + "'}",
use this
data: {lastName:_lname,firstName:_fname,middleName:_mname},

Answer 4

try with this solution
$lastname = isset($_POST['lastName'])?json_decode($_POST['lastName']):null; $firstname =isset($_POST['firstname'])?json_decode($_POST['firstname']):null; $middlename=isset($_POST['middlename'])?json_decode($_POST['middlename']):null;