How can PHP be used to ensure that a new page opens within the same window?

To ensure that a new page opens within the same window in PHP, you can use the header() function to set the "Location" header to the desired URL. This will redirect the user to the new page within the same window.

<?php
$newPageUrl = "https://www.example.com/newpage.php";
header("Location: $newPageUrl");
exit();
?>