Php $var returning no value inside HTML - php

Question

I have a variable $success set to $success = "Successfully Created" but the var $success has no value inside HTML.
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// username and password sent from form
if (isset($_POST['okbutton'])) {
if (isset($_POST['clientuser'], $_POST['clientpass'])) {
$clientuser = $_POST['clientuser'];
$clientpass = $_POST['clientpass'];
$_SESSION['cuser'] = $clientuser;
$_SESSION['cpass'] = $clientpass;
header('Location: trialaccount.php');
die();
}
}
}
try {
if (isset($_SESSION['cuser'])) {
$stmt = $conn->prepare("SELECT user_id FROM user WHERE user_id=:username");
$stmt->bindParam(':username', $_SESSION['cuser']);
$stmt->execute();
$checkdup = $stmt->rowCount();
if ($checkdup == 0) {
$stmt = $conn->prepare("INSERT INTO user (user_id, user_pass, user_online, user_enable, user_start_date, user_end_date, reseller, type) VALUES (:clientuser, :clientpass,0, 1, now(), now() + interval 4 hour, :panelUSER, 'Trial')");
$stmt->bindParam(':clientuser', $_SESSION['cuser']);
$stmt->bindParam(':clientpass', $_SESSION['cpass']);
$stmt->bindParam(':panelUSER', $username);
$stmt->execute();
$success = "Trial Account Created Successfully!";
} else {
$error = "Username '" . $_SESSION['cuser'] . "' is already taken. Try to input unique username." ;
}
}
} catch (PDOException $e) {
echo "Error: Database Error";
}
Inside my HTML, I use echo!
<?php if(isset($success)){ echo $success; } ?>
var $success is returning the value on my personal smartphone,
but no value on other devices.
I dont know what is happening?
Can I use Session instead? ty

Answer 1

Your method does not get the total row count. Therefore, it doesn't go through (if($checkdup == 0)) to set the value for $success. You can try the code below.
Replace:
$stmt = $conn->prepare("SELECT user_id FROM user WHERE user_id=:username");
$stmt->bindParam(':username', $_SESSION['cuser']);
$stmt->execute();
$checkdup = $stmt->rowCount();
With:
$stmt = $conn->prepare("SELECT COUNT(*) FROM user WHERE user_id=:username");
$stmt->bindParam(':username', $_SESSION['cuser']);
$stmt->execute();
$checkdup = $stmt->fetchColumn();