How can JavaScript and PHP be combined to create interactive form elements like dropdown menus?

To create interactive form elements like dropdown menus, JavaScript can be used to dynamically update the options in the dropdown based on user input. PHP can be used to generate the initial options for the dropdown menu based on data from a database or other source. By combining JavaScript and PHP, you can create dynamic and interactive form elements that provide a better user experience.

<select id="dropdown">
<?php
// PHP code to generate options for the dropdown menu
$options = array("Option 1", "Option 2", "Option 3");
foreach ($options as $option) {
    echo "<option value='$option'>$option</option>";
}
?>
</select>