session_03.php

<?php
session_start();
ob_start();
?>
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Session test 3</title>
</head>

<body>
<?php
// check whether session variable is set
if (isset($_SESSION['name'])) {
  // if set, greet by name
  echo 'Hi, ' . $_SESSION['name'] . '. See, I remembered your name!<br>';
  // unset session variable
  unset($_SESSION['name']);
  // invalidate the session cookie
  if (isset($_COOKIE[session_name()])) {
    setcookie(session_name(), '', time()-86400, '/');
  }
  ob_end_flush();
  // end session
  session_destroy();
  echo '<a href="session_02.php">Page 2</a>';
} else {
  // display if not recognized
  echo "Sorry, I don't know you.<br>";
  echo '<a href="session_01.php">Login</a>';
}
?>
</body>
</html>