HTML5中的DataTransfer对象
所有拖放事件的事件侦听器方法都接受具有名为dataTransfer的只读属性的Event对象。event.dataTransfer返回与事件关联的DataTransfer对象，如下所示：
function EnterHandler(event) {
DataTransfer dt = event.dataTransfer;
…
}您可以尝试运行以下代码来实现DataTransfer对象：
<!DOCTYPE HTML>
<html>
<head>
<style>
#boxA, #boxB { float:left;padding:10px;margin:10px; -moz-user-select:none; }
#boxA { background-color: #6633FF; width:75px; height:75px; }
#boxB { background-color: #FF6699; width:150px; height:150px; }
</style>
<script>
function dragStart(ev) {
ev.dataTransfer.effectAllowed='move';
ev.dataTransfer.setData("Text", ev.target.getAttribute('id'));
ev.dataTransfer.setDragImage(ev.target,0,0);
return true;
}
</script>
</head>
<body>
<center>
<h2>Drag and drop HTML5 demo</h2>
<div>Try to drag the purple box around.</div>
<div id = "boxA" draggable = "true" ondragstart = "return dragStart(ev)">
<p>Drag Me</p>
</div>
<div id = "boxB">Dustbin</div>
</center>
</body>
</html>