HTML拖放元素

实现来回拖放图片
<!DOCTYPE HTML>
<html>
    <title>来回拖放元素</title>
    <meta charset="utf-8">
<head>
<style type="text/css">
#div1 {198px; height:200px;padding:10px;border:1px solid #aaaaaa;}
#div2 {198px; height:200px;padding:10px;border:1px solid #aaaaaa;}
img:hover{cursor: pointer;}
</style>
<script type="text/javascript">
function allowDrop(ev)
{
ev.preventDefault();
}

function drag(ev)
{
ev.dataTransfer.setData("img",ev.target.id);
}

function drop(ev)
{
ev.preventDefault();
var data=ev.dataTransfer.getData("img");
ev.target.appendChild(document.getElementById(data));
}
</script>
</head>
<body>
<p>请把 W3School 的图片拖放到矩形中：</p>
<div id="div1" ondrop="drop(event)" ondragover="allowDrop(event)"></div>
<br />
<div id="div2" ondrop="drop(event)" ondragover="allowDrop(event)">
    <img id="drag1" src="1.jpg" draggable="true" ondragstart="drag(event)" />
</div>
</body>
</html>