title: PHP - Add form element before submit - Buy Button
body: <p>I need to dynamically add form elements to an HTML form as soon as the Submit button is clicked but before the POST data is sent to a server. The new elements must be "read" from a PHP file on my server.</p>
  
  <p>HISTORY:
  Currently my HTML form has "hidden" fields that are submitted to another server for processing. I have no control over the other server. My problem is that anyone can edit these hidden fields.</p>
  
  <p>How can I dynamically add form elements to the POST data as soon as the form is submitted?</p>