How can JavaScript be used to enhance the auto-completion functionality in a PHP application?

To enhance the auto-completion functionality in a PHP application, JavaScript can be used to make asynchronous requests to the server to fetch relevant data based on user input. This data can then be displayed in a dropdown list for the user to select from, providing a more seamless auto-completion experience.

<?php

// PHP code to handle the auto-completion functionality

// Assuming $data is an array of possible auto-completion suggestions

$input = $_GET['input'];

$matches = [];

foreach ($data as $item) {
    if (stripos($item, $input) !== false) {
        $matches[] = $item;
    }
}

echo json_encode($matches);