div与div之间的拖拽

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
#div1, #div2{float:left; width:100px; height:100px; border:1px solid #aaaaaa;}
</style>
</head>
<body>

<!-- 拖拽目标：ondrop接收拖拽完成时处理，ondragover拖拽上目标时处理 -->
<div id="div1" ondrop="drop(event)" ondragover="allowDrop(event)">
<!-- 拖动源：draggable允许拖拽，ondragstart拖拽开始时处理 -->
<img id="drag1" draggable="true" ondragstart="drag(event)" src="https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=1848039140,2563753692&fm=200&gp=0.jpg" width="100px" />
</div>
<!-- 拖拽目标：ondrop接收拖拽完成时处理，ondragover拖拽上目标时处理 -->
<div id="div2" ondrop="drop(event)" ondragover="allowDrop(event)"></div>
</body>
</html>
<script type="text/javascript">
// 拖拽源：开始拖拽，存储拖动元素的id
function drag(ev){
ev.dataTransfer.setData("data",ev.target.id

);
}
// 拖拽目标：允许接收拖动
function allowDrop(ev){ ev.preventDefault(); }
// 拖动目标：接收拖拽数据进行处理
function drop(ev){
ev.preventDefault();

var data=ev.dataTransfer.getData("data");
console.log(data);
console.log(ev);
ev.target.appendChild(document.getElementById(data));

}

</script>