Success Messages on Form Submission in PHP

Let's now make it so that after the redirect to the page, a message about the successful save is displayed. We will use flash messages for this:

php<?php
  session_start();
  
  if (!empty($_POST)) {
    // save to database
    
    $_SESSION['flash'] = 'form successfully saved';
    header('Location: form.php');
    die();
  }
  
  if (isset($_SESSION['flash'])) {
    echo $_SESSION['flash'];
    unset($_SESSION['flash']);
  }
?>