How do I detect a file is being dragged rather than a draggable element on my page?

I'm using the html5 events to enable both file and element drag-and-drop. I've attached the dragover event to the body and am using event delegations to show where a draggable can be dropped. My question is how can I tell if a file is being dragged vs. an element with draggable=true. I know I can detect the element being dragged via e.target. But, how can I tell if it is a file.

jquery is available.

Also, not talking about jquery-ui draggable here.

I'm starting to think maybe the only way to detect the file will be by exclusion and detecting the elements instead. If we're not dragging an element, assume it's a file. This will require extra work though as images and links are draggable by default, so I will have to add events to them or prevent them from dragging.

You can detect what is being dragged by inspecting dataTransfer.types. This behaviour is not (yet) consistent across browsers so you have to check for the existence of 'Files' (Chrome) and 'application/x-moz-file' (Firefox).

// Show the dropzone when dragging files (not folders or page
// elements). The dropzone is hidden after a timer to prevent 
// flickering to occur as `dragleave` is fired constantly.
var dragTimer;
$(document).on('dragover', function(e) {
  var dt = e.originalEvent.dataTransfer;
  if (dt.types && (dt.types.indexOf ? dt.types.indexOf('Files') != -1 : dt.types.contains('Files'))) {
    $("#dropzone").show();
    window.clearTimeout(dragTimer);
  }
});
$(document).on('dragleave', function(e) {
  dragTimer = window.setTimeout(function() {
    $("#dropzone").hide();
  }, 25);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="dropzone" style="border: 2px dashed black; background: limegreen; padding: 25px; margin: 25px 0; display: none; position">
  🎯 Drop files here!
</div>
📄 hover files here

Further improvement of bouke's answer:

Since chrome calls dragleave of document on every dragenter foe each element, it can cause flickering of the dropzone, especially if there are many nested elements.

$(document).on('dragleave', function(e) {
    dragTimer = window.setTimeout(function() {
        $("#dropzone").hide();
        }, 25);
});

What I did to fix the issue for me is increasing the timeout a bit and adding clearTimeout before setting each timeout, since previously in some cases there would be more than one timeouts which are not cleared in the dragover event, since dragTimer stores only the latest one. The result version:

$(document).on('dragleave', function(e) {
    window.clearTimeout(dragTimer);
    dragTimer = window.setTimeout(function() {
        $("#dropzone").hide();
    }, 85);
});

btw, thanks for the idea! My other solution was an absolute pain :)

I just use this to detect files in dragover event:

Array.prototype.indexOf.call(files, "Files")!=-1 // true if files