$firstName = "John"; $lastName = "Doe"; $return_message = "Welcome to our website, ".$firstName." ".$lastName."!"; echo $return_message;
if($login_successful) { $return_message = "Welcome back, ".$user_name."!"; } else { $return_message = "Invalid credentials. Please try again."; } echo $return_message;In this example, we have used an if-else statement to determine whether the user's login credentials are valid or not. If the login is successful, a personalized welcome message is displayed. Otherwise, an error message is displayed. These examples do not seem to depend on any specific package or library. However, PHP has a huge collection of third-party libraries and frameworks that can be used to develop complex web applications with ease. Some popular PHP libraries include Symfony, Laravel, and CodeIgniter.