PHP test_input

test_input.php

<?php
// define variables and set to empty values
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $name = test_input($_POST["name"]);
  $email = test_input($_POST["email"]);
  $website = test_input($_POST["website"]);
  $comment = test_input($_POST["comment"]);
  $gender = test_input($_POST["gender"]);
}

function test_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}
?>

if ($_SERVER["REQUEST_METHOD"] == "POST") {
        if (empty($_POST["name"])) {
          $name_err = "Name is required";
        } else {
          $name = test_input($_POST["name"]);
          // check if name only contains letters and whitespace
          if (!preg_match("/^[a-zA-Z-' ]*$/",$name)) {
            $nameErr = "Only letters and white space allowed";
          }
        }
        
        if (empty($_POST["email"])) {
          $email_err = "Email is required";
        } else {
          $email = test_input($_POST["email"]);
          // check if e-mail address is well-formed
          if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $email_err= "Invalid email format";
          }
        }

here is a long way in solving it also.