What are the key differences between using JavaScript and PHP for handling button locking functionality?

When handling button locking functionality, the key difference between using JavaScript and PHP is that JavaScript operates on the client-side, allowing for immediate feedback to the user without page reloads, while PHP operates on the server-side, requiring a page refresh to see changes. To implement button locking functionality using PHP, you can disable the button after it is clicked by adding a disabled attribute to the button element. This prevents the user from clicking the button multiple times and submitting the form multiple times.

<form action="submit.php" method="post">
  <input type="submit" name="submit" value="Submit" <?php if(isset($_POST['submit'])) echo 'disabled'; ?>>
</form>