chromium/third_party/blink/web_tests/external/wpt/html/editing/dnd/cross-document/003.html

<!DOCTYPE html>
<title>drag &amp; drop - cross-document variable retention within event handlers</title>
<style>
  body > div {
    height: 200px;
    width: 200px;
    background-color: orange;
  }
</style>

<script>
var evs = {};
window.onload = function() {
  var orange = document.getElementsByTagName('div')[0];
  orange.ondragstart = function(e) {
    e.dataTransfer.effectAllowed = 'copy';
    e.dataTransfer.setData('text', 'dummy text');
    evs[e.type] = {};
    evs[e.type].dataTransfer = e.dataTransfer;
    evs[e.type].items = e.dataTransfer.items;
    evs[e.type].types = e.dataTransfer.types;
    evs[e.type].files = e.dataTransfer.files;
  };
};
</script>

<div draggable="true"></div>
<p><iframe src="003-1.html" height="300" width="500"></iframe></p>
<noscript><p>Enable JavaScript and reload</p></noscript>