<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Dropping image on horizontal iframe scrollbar</title>
<style type="text/css">
p:first-child
  {padding-left:1em;}
iframe
  {height:3em;
  width:4em;}
img
  {width:5px;
  height:5px;}
</style>
<script type="application/ecmascript">
function dragImage()
  {event.dataTransfer.effectAllowed = 'copy';}
function dropImage(event)
  {document.querySelector('p + p').firstChild.nodeValue = 'PASS';}
</script>
</head>
<body