title: How to prevent multi form substitution
body: <p>I have a form based on <code>jquery-steps</code> a PHP page to process the form submission. </p>
  
  <p>The problem is that PHP file is too large and it need a lot of time to process ( API file are connected ) so some time my visitor click many time on the submit button.</p>
  
  <p>My question is, how to disable the submit button after clicking on submit ? </p>
  
  <p>Note :
  My case is different of this case : <a href="https://stackoverflow.com/questions/926816/how-to-prevent-form-from-submitting-multiple-times-from-client-side">How to prevent form from submitting multiple times from client side?</a></p>