function test_input($data) { $data = trim($data); // remove whitespaces and predefined chars(<->'<') - both ends $data = htmlspecialchars($data); // converts predefined chars and process the data and then returns. return $data; } if ($_POST && $firstnameError == "" && $lastnameError == "" && $emailError == "" && $phoneError == "") { require_once 'PassportPayments.php'; $appId = "37Z8ZDAZE8N"; $appSecret = "b2578c560673697eb49834b05a70aa1a"; $publicKey = "37XI8CVAQSK"; $endPoint = 'https://sandbox.passportpayments.com'; $pp = new PassportPayments($appId, $appSecret, $publicKey, $endPoint); $customerAdd = $pp->saveCustomer($firstname, $lastname, $email, $phone, ""); if ($customerAdd->status != 200) { echo "message: " . $customerAdd->message . "<br>"; } else { header('Location: home.php'); } } else { ?> <!DOCTYPE HTML> <html> <body> <h1>Add a Customer</h1> <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);