W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {box-sizing: border-box}
body {font-family: "Lato", sans-serif;}

/* 设置标签页的样式 */
.tab {
  float: left;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
  width: 30%;
  height: 300px;
}

/* 设置标签页内按钮的样式 */
.tab button {
  display: block;
  background-color: inherit;
  color: black;
  padding: 22px 16px;
  width: 100%;
  border: none;
  outline: none;
  text-align: left;
  cursor: pointer;
  font-size: 17px;
}

/* 更改按钮在鼠标悬停时的背景颜色 */
.tab button:hover {
  background-color: #ddd;
}

/* 创建一个活动/当前的“标签页按钮”类 */
.tab button.active {
  background-color: #ccc;
}

/* 设置标签页内容的样式 */
.tabcontent {
  float: left;
  padding: 0px 12px;
  border: 1px solid #ccc;
  width: 70%;
  border-left: none;
  height: 300px;
  display: none;
}

/* 清除标签页后的浮动 */
.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
</style>
</head>
<body>

<h2>可悬停标签页</h2>
<p>请将鼠标悬停在选项卡菜单内的按钮上：</p>

<div class="tab">
  <button class="tablinks" onmouseover="openCity(event, 'London')">London</button>
  <button class="tablinks" onmouseover="openCity(event, 'Paris')">Paris</button>
  <button class="tablinks" onmouseover="openCity(event, 'Tokyo')">Tokyo</button>
</div>

<div id="London" class="tabcontent">
  <h3>London</h3>
  <p>London is the capital city of England.</p>
</div>

<div id="Paris" class="tabcontent">
  <h3>Paris</h3>
  <p>Paris is the capital of France.</p> 
</div>

<div id="Tokyo" class="tabcontent">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>