SOURCE

function dragStart(event) {
    event.dataTransfer.setData("Text", event.target.id);
}
function allowDrop(event) {
    event.preventDefault();
    document.getElementById("demo").innerHTML = " p 元素在放置目标上";
    event.target.style.border = "4px dotted green";
}
function drop(event) {
    event.preventDefault();
    var data = event.dataTransfer.getData("Text");
    event.target.appendChild(document.getElementById(data));
    document.getElementById("demo").innerHTML = " p 元素被拖动";
}

<p ondragstart="dragStart(event)" draggable="true" id="dragtarget">把我拖动到矩形框中！</p>
<div id="droptarget" ondrop="drop(event)" ondragover="allowDrop(event)">
</div>
<p style="clear:both;"><strong>注意：</strong>Internet Explorer 8 及更早 IE 版本或 Safari 5.1 及更早版本的浏览器不支持 drag 事件。</p>
<p id="demo"></p>

#droptarget {
    float: left; 
    width: 200px; 
    height: 35px;
    margin: 55px;
    margin-top: 155px;
    padding: 10px;
    border: 1px solid #aaaaaa;
}