<!DOCTYPE html>
<html>
  <head>
    <title>Drag and drop with middle click over Flash</title>
    <style type="text/css">
div {
  width: 100px;
  height: 100px;
  background: fuchsia;
}
object {
  width: 400px;
  height: 400px;
  border: 5px solid black;
}
    </style>
    <script type="text/javascript">
window.onload = function () {
  document.getElementsByTagName('div')[0].ondragstart = function (e) {
    e.dataTransfer.effectAllowed = 'copy';
    e.dataTransfer.setData('text','dummy text');
  };
};
    <