Is it possible to interact with a Java applet using PHP, particularly in terms of filling out form fields and clicking buttons?

It is not possible to directly interact with a Java applet using PHP as they are two different technologies that run on the client-side and server-side respectively. However, you can use JavaScript to interact with the Java applet on the client-side. You can trigger events like filling out form fields and clicking buttons using JavaScript in conjunction with the Java applet.

// PHP code to interact with a Java applet using JavaScript

echo '<script>';
echo 'document.getElementById("appletId").formField.value = "value";'; // Fill out form field
echo 'document.getElementById("appletId").button.click();'; // Click button
echo '</script>';