title: drag and drop working in chrome, not firefox
body: <p>Here's an example of drag&amp;drop images (provided from course "HTML5 power workshop" by Andy Olsen) : 
  <a href="http://aorbaroquethrash.com/dragdrop/" rel="nofollow noreferrer">http://aorbaroquethrash.com/dragdrop/</a></p>
  
  <p>You have to drag an image from your desktop to the yellow square.</p>
  
  <p>It is working in chrome, but not firefox, why ?</p>
  
  <p>There's a similar post : 
  <a href="https://stackoverflow.com/questions/18269677/drag-and-drop-not-working-in-firefox">drag and drop not working in firefox</a>
  It says to use "dataTransfer.setData", but I don't think it applies to my example.</p>
  
  <p>In my example I use 
  <code>var allTheFiles = event.dataTransfer.files;</code>
  ...</p>
  
  <p>PatricK</p>