What are some alternative methods to redirect to a new page in PHP, besides header("Location: ")?

When redirecting to a new page in PHP, using the header("Location: ") function is a common method. However, in some cases, this method may not work due to headers already being sent or other issues. In such situations, an alternative method to redirect to a new page in PHP is to use JavaScript to perform the redirect on the client-side.

echo '<script>window.location.href = "newpage.php";</script>';