title: Show AJAX upload status on progress element
body: <p>I have an AJAX script to upload a file to a PHP script that is likely to take at least 10 seconds to run. I would like to display progress for it for the user.</p>
  <p>In the executing class, I have a property <code>$progress</code> which is updated with the progress (in 1-100), and a method <code>get_progress()</code> (which's purpose should be obvious).</p>
  <p>The question is, how to update the <code>&lt;progress&gt;</code> element on the front end for the user to see?</p>
  <p>I think AJAX is the solution, but I just can not get my head around it. I can not get to the same object instance.</p>