基于JavaScript实现选项卡效果

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>选项卡</title>
  <style type="text/css"> 
    #div1 .active{
      background: red;
      color: white;
    }
    #div1 div{
      width: 237px;
      height:150px;
      background:#CCC;
      display: none;
    }

  </style>
  <script type="text/javascript">
    window.onload=function(){
      var oDiv = document.getElementById('div1');
      var btn = oDiv.getElementsByTagName('input');
      var aDiv = oDiv.getElementsByTagName('div');

      for (var i = 0; i < btn.length; i++) {
        btn[i].index=i;
        //给btn增加一个index的属性
        btn[i].onmouseover = function(){
          for (var i = 0; i < btn.length; i++) {
            btn[i].className = '';
            aDiv[i].style.display = 'none';
          }
          this.className = 'active';

          aDiv[this.index].style.display = 'block';

          //调用index属性
        }
      }
    };
  </script>
</head>
<body>
  <div id="div1">
    <input type="button" value="首页" class="active">
    <input type="button" value="菜单">
    <input type="button" value="帮助">
    <input type="button" value="联系">
    <input type="button" value="赞助">
    <div style="display: block;">这是首页</div>
    <div>这是菜单</div>
    <div>这是帮助</div>
    <div>这是联系</div>
    <div>这是赞助</div>
  </div>
</body>
</html>