AJAX responseText is unreliable - php

Question

I'm trying to send form data to a php script without a redirect.
The problem i have is that the responseText function doesn't seem to work reliably.
NOTE: The PHP script works as intended. And is writing to the database and so on.
AJAX code:
$(document).ready(function(){
$('#registreer').click(function(){
$.ajax({
type: "POST",
url: "assets/PHP/registreer.php",
data: $('form').serialize(),
success: function(jqXHR, textStatus) {alert("Succes" + jqXHR.responseText);},
error: function(jqXHR, textStatus) {alert("Error" + jqXHR.responseText);}
})
});
});
PHP code:
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
if ($passwordPost != $passwordRetypePost) {
echo "Paswoorden zijn niet hetzelfde!";
} else {
if (!($stmt = $conn->prepare("SELECT * FROM `Gebruikers` WHERE `Email` = ?"))) {
echo "Prepare failed: (" . $conn->errno . ") " . $conn->error;
} else {
$stmt->bind_param("s", $emailPost);
$stmt->execute();
$stmt->bind_result($id, $email, $paswoord, $rol);
$stmt->store_result();
if ($stmt->num_rows > 0) {
echo "Email bestaat al!";
} else {
$stmt->close();
$hash = password_hash($passwordPost, PASSWORD_DEFAULT);
if (!($stmt = $conn->prepare("INSERT INTO `Gebruikers`(`Email`, `Paswoord`) VALUES (?,'$hash')"))) {
echo "Prepare failed: (" . $conn->errno . ") " . $conn->error;
}
$stmt->bind_param("s", $emailPost);
$stmt->execute();
echo 'Gelukt!';
}
}
}
$mysqli->close();
So for some reason the only response i can get is:
echo "Email bestaat al!";
All the other echo's do not seem to be working on my HTML page. No matter what i try.
Any suggestions are welcome!

Answer 1

You receive that message because you're checking if there is already the $emailPost in the database and the answer is true. This is why you've received this message.
Have you tried with another email adress ?
Also, in your jQuery callbacks (success and error) you will always receive "success" things, because you doesn't throw any error, in any case, on the PHP side.
You should better use something like throw new Exception('Prepare failed[...]') on every 'echo' or 'die' statement that you have in php, except for the success one where you can correctly use echo 'Gelukt!';.