How can PHP be used in conjunction with JavaScript to achieve desired page redirection within an iframe?

To achieve page redirection within an iframe using PHP and JavaScript, you can have PHP generate the JavaScript code necessary for the redirection. This can be done by using PHP to echo out JavaScript code that sets the iframe's `src` attribute to the desired URL for redirection.

<?php
  // PHP code to generate JavaScript for iframe redirection
  echo '<script>';
  echo 'document.getElementById("myIframe").src = "https://www.example.com/newpage.php";';
  echo '</script>';
?>