In the provided PHP and JavaScript code snippets, what are some potential pitfalls or errors that could prevent the AJAX request from functioning correctly?

One potential pitfall that could prevent the AJAX request from functioning correctly is not setting the correct headers in the PHP script to allow cross-origin requests. To solve this issue, the PHP script should include the header "Access-Control-Allow-Origin: *" to allow requests from any origin.

header("Access-Control-Allow-Origin: *");

// Your existing PHP code here