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chromium/third_party/blink/web_tests/external/wpt/html/editing/dnd/file/010.html 

<!DOCTYPE html>
<title>drag &amp; drop - blocked drop</title>
<style>
  body > div {
    height: 200px;
    width: 200px;
    background-color: orange;
  }
</style>

<script>
//This test assumes that if the page does not want to use the drop, that the browser will revert to default behaviour of opening the file
window.onload = function() {
  var orange = document.getElementsByTagName('div')[0];
  orange.ondragover = orange.ondragenter = function(e) {
    e.preventDefault();
    e.dataTransfer.dropEffect = 'none';
  };
  orange.ondrop = function(e) {
    e.preventDefault();
  };

};
</script>

<div></div>

<p>Save <a href="../resources/pass.png">this image</a> to your desktop. Use your pointing device to drag the saved file from your desktop onto the orange box, and release it. Fail if nothing happens.</p>
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