<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Selection drag and drop: setting dropzone attribute ondragstart</title>
<style type="text/css">
div
  {display:inline-block;
  vertical-align:top;
  background-color:olive;
  color:white;
  padding:20px;
  width:100px;
  height:100px;}
div:nth-child(2)
  {background-color:green;}
div:nth-child(3)
  {background-color:teal;}
</style>
<script type="application/ecmascript">
var effects = ['copy','move','link'];
function selectText()
  {window.getSelection().selectAllChildren(document.querySelector('p'))}
function dropSelection(event,element)
  {document.querySelectorAll('div')[element].appendChild(document.createTextNode((event.dataTransfer.dropEffect == effects[element])?' PASS ':' FAIL '));
  selectText();}
function start(event)
  {for(var i = 0; i != 3; i++)
    {document.querySelectorAll('div')[i].setAttribute('dropzone',effects[i] + ' string:text/plain')}
  }
</script>
</head>
<body onload="selectText()">
<div ondrop="dropSelection(event,0)"/>
<div ondrop="dropSelection(event,1)"/>
<div ondrop="dropSelection(event,2)"/>
<p ondragstart="start(event)">Drag me</p>
<p>You should be able to drag selection and drop it onto any of the green boxes.</p>
</body>
</html>