JS---案例：筋斗云

案例：筋斗云

鼠标进入，一朵云的样式跟随鼠标移动，鼠标点击后离开，云样式回到上次点击的位置
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title></title>
  <style>
    * {
      margin: 0;
      padding: 0
    }

    ul {
      list-style: none
    }

    body {
      background-color: #333;
    }

    .nav {
      width: 800px;
      height: 42px;
      margin: 100px auto;
      background: url(images/rss.png) right center no-repeat;
      background-color: #fff;
      border-radius: 10px;
      position: relative;
    }

    .nav li {
      width: 83px;
      height: 42px;
      text-align: center;
      line-height: 42px;
      float: left;
      cursor: pointer;
    }

    .nav span {
      position: absolute;
      top: 0;
      left: 0;
      width: 83px;
      height: 42px;
      background: url(images/cloud.gif) no-repeat;
    }

    ul {
      position: relative;
    }
  </style>
</head>

<body>
  <div class="nav">
    <span id="cloud"></span>
    <ul id="navBar">
      <li>北京校区</li>
      <li>上海校区</li>
      <li>广州校区</li>
      <li>深圳校区</li>
      <li>武汉校区</li>
      <li>关于我们</li>
      <li>联系我们</li>
      <li>招贤纳士</li>
    </ul>
  </div>
  <script src="common.js"></script>
  <script>

    //获取云彩
    var cloud = my$("cloud");
    //获取所有的li标签
    var list = my$("navBar").children;
    //循环遍历分别注册鼠标进入，鼠标离开，和鼠标点击事件
    for (var i = 0; i < list.length; i++) {
      //鼠标进入事件
      list[i].onmouseover = mouseoverHandle;
      //鼠标点击事件
      list[i].onclick = clickHandle;
      //鼠标离开事件
      list[i].onmouseout = mouseoutHandle;
    }
    function mouseoverHandle() { //进入
      //移动到鼠标此次进入的li的位置
      animate(cloud, this.offsetLeft);
    }
    //点击的时候，记录此次点击的位置
    var lastPosition = 0;
    function clickHandle() {//点击
      lastPosition = this.offsetLeft;
    }
    function mouseoutHandle() {//离开
      animate(cloud, lastPosition);
    }

  </script>
</body>

</html>
原文地址：https://www.cnblogs.com/jane-panyiyun/p/12059310.html