尝试一下》

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <style>
    div {
      position: absolute;
    }

    #container div {
      background-color: lightblue;
      border: 1px solid #333333;
      width: 100px;
      height: 100px;
      opacity: 0.5;
    }

    div#myBox {
      opacity: 1;
      background-color: coral;
      z-index: 1;
      -webkit-animation: mymove 5s infinite linear;
      /* Chrome, Safari, Opera */
      animation: mymove 5s infinite linear;
    }
    /* Chrome, Safari, Opera */

    @-webkit-keyframes mymove {
      50% {
        z-index: 5;
      }
    }
    /* Standard syntax */

    @keyframes mymove {
      50% {
        z-index: 5;
      }
    }
  </style>
</head>
<body style="position:absolute">

  <p>z-index 属性支持动画效果。</p>
  <p><b>注意：</b>Internet Explorer 9 及更早 IE 版本不支持 CSS 动画。</p>

  <p>逐步改变 "myBox" 的 z-index 属性 从 1 到 5:
    <p>
      <div id="container">
        <div id="myBox">myBox</div>
        <div style="top:20px;left:20px;z-index:1;">z-index 1</div>
        <div style="top:40px;left:40px;z-index:2;">z-index 2</div>
        <div style="top:60px;left:60px;z-index:3;">z-index 3</div>
        <div style="top:80px;left:80px;z-index:4;">z-index 4</div>
      </div>

</body>
</html>
        
尝试一下 》
