$_POST not being set with AJAX Post value - php

Question

I'm trying to send a JSON object to a .php file. What troubles me is that my POST value doesn't seem to get into PHP's $_POST array. Here is my code:
jQuery:
$("#submit").click(function(){
var obj = { //create json object to be sent
"name": $("#name").val(),
"email": $("#email").val(),
"r1": $("#r1").val(),
"r2": $("#r2").val(),
"r3": $("#r3").val(),
"intr1": $("#q1").val(),
"intr2": $("#q2").val(),
"intr3": $("#q3").val(),
"set": "set1"
};
var jsonObj = JSON.stringify(obj);
$.post(
"updateAnswers.php",
jsonObj,
function() {
//location.href = 'set2.php';
}
);
})
PHP:
if (isset($_POST["jsonObj"])) { // value is empty
$obj = json_decode($_POST['jsonObj'], true);
$name = $obj['name'];
$email = $obj['email'];
$db = mysqli_connect("localhost", "root", "", "concurs");
$sql="INSERT into players values ('$name', '$email', '0', '0', '0')";
mysqli_query($db, $sql);
}
Thanks in advance!

Answer 1

I dont think you need to stringify obj - try passing obj straight to the $.post function.
$.post("updateAnswers.php", obj, function() {
//location.href = 'set2.php';
});
On the PHP side, the values name, email, r1, etc.. will be directly in the $_POST array.. so you will need to access $_POST['name'] and so on.
echo "Name: ". $_POST['name']; //Show name value
var_dump($_POST); //Show all passed values
Your $sql string does not check for SQL injection. You must (at the very least) replace single quotes with two single quotes like:
$sql = "INSERT into players values ('".str_replace("'","''", $name). "', '".str_replace("'","''", $email). "', '0', '0', '0')";

Answer 2

You are using stringify on your obj and then you pass it to the ajax-function.
But the ajax-function expects the object as objetct not as string.
So just remove var jsonObj = JSON.stringify(obj); and just use obj
Furtermore you have to check for
name
email
r1
...
in your php-script instead of jsonObj because thats what the php actually gets from your script

Answer 3

This with AJAX() send:
$.ajax({
type: 'POST',
url: 'updateAnswers.php',
data: {'jsonObj': jsonObj},
success: function(msg) {
alert(msg);
}
});