What is the concept of dynamic content in PHP and how can it be implemented effectively?

Dynamic content in PHP refers to content that changes based on user input, database queries, or other external factors. To implement dynamic content effectively, you can use PHP to generate HTML content dynamically based on these factors. This can include displaying different information based on user input, fetching data from a database, or generating content based on the current date or time. Example PHP code snippet:

<?php
// Example of dynamically generating content based on user input
$user_input = $_GET['user_input'];

if ($user_input == 'hello') {
    echo '<h1>Hello, world!</h1>';
} else {
    echo '<h1>Goodbye, world!</h1>';
}
?>