javascript拖拽操作

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style type="text/css">
  #target {
    width: 500px;
    height: 300px;
    line-height: 300px;
    text-align: center;
    border: 3px dashed #ccc;
  }

  #target.active {
    background: #eee;
    box-shadow: 2px 2px 2px #eee;
  }
  </style>
</head>

<body>
  <div class="container">
    <div class="content">
      <img src="toy.png">
      <p>选择文字拖到目标位子</p>
    </div>
    <div id="target">
      <span>拖动文字到这里</span>
    </div>
  </div>
  <script type="text/javascript">
  (function() {
    var target = document.querySelector('#target');
    target.addEventListener('dragenter', function() {
      this.classList.add('active');
    })
    target.addEventListener('dragleave', function() {
      this.classList.remove('active');
    })
    //阻止冒泡和默认行为
    target.addEventListener('dragover', function(e) {
      e.preventDefault();
      e.stopPropagation();
    })

    //目标框得到drop事件
    target.addEventListener('drop', function(e) {
      var data = e.dataTransfer.getData('text/plain');
      var imgSrc = e.dataTransfer.getData('text/uri-list');
      if (data) {
        // 拖入的是文本
        target.innerHTML = data;
      } else if (imgSrc) {
        var img = document.createElement('img');
        img.src = imgSrc;
        target.appendChild(img);
      }
      this.classList.remove('active');
      e.preventDefault();
      e.stopPropagation();
    })
  })()
  </script>
</body>

</html>