connect_error) { die("Connection failed: " . $conn->connect_error); } ?>
4. .php3 and .php4 - These PHP file extensions were used in older versions of PHP but are no longer recommended for use. They are not associated with any specific package library. In terms of package libraries, there are many libraries available for PHP depending on the specific functionality needed. Some popular PHP libraries include: - Laravel: a web application framework for PHP - Symfony: a set of reusable PHP components and a web application framework - Guzzle: a PHP HTTP client library - Swift Mailer: a library for sending emails from PHP - PHPMailer: another library for sending emails from PHP.