Chuyển tab khi hover bằng CSS và JavaScript

Để chuyển tab khi hover với CSS và JavaScript, code như sau:

Ví dụ

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    * {box-sizing: border-box}
    .tab {
      float: left;
      border: 1px solid #ccc;
      background-color: #f1f1f1;
      width: 30%;
      height: 300px;
    }
    .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;
    }
    .tab button:hover {
      background-color: #ddd;
    }
    .tab button.active {
      background-color: #ccc;
    }
    .tabcontent {
      float: left;
      padding: 0px 12px;
      border: 1px solid #ccc;
      width: 70%;
      border-left: none;
      height: 300px;
      display: none;
    }
    .clearfix::after {
      content: "";
      clear: both;
      display: table;
    }
  </style>
</head>
<body>
  <h2>Demo Heading Tabs</h2>
  <p>Get the Department info by hovering over tabs:</p>
  <div class="tab">
    <button class="tablinks" onmouseover="demo(event, 'Marketing')">Marketing</button>
    <button class="tablinks" onmouseover="demo(event, 'Operations')">Operations</button>
    <button class="tablinks" onmouseover="demo(event, 'Finance')">Finance</button>
    <button class="tablinks" onmouseover="demo(event, 'IT')">IT</button>
  </div>
  <div id="Marketing" class="tabcontent">
    <h3>Marketing</h3>
  </div>
  <div id="Operations" class="tabcontent">
    <h3>Operations</h3>
  </div>
  <div id="Finance" class="tabcontent">
    <h3>Finance</h3>
  </div>
  <div id="IT" class="tabcontent">
    <h3>IT</h3>
  </div>
  <div class="clearfix"></div>
  <script>
    function demo(e, dept) {
      var i, content, links;
      content = document.getElementsByClassName("tabcontent");
      for (i = 0; i < content.length; i++) {
        content[i].style.display = "none";
      }
      links = document.getElementsByClassName("tablinks");
      for (i = 0; i < links.length; i++) {
        links[i].className = links[i].className.replace(" active", "");
      }
      document.getElementById(dept).style.display = "block";
      e.currentTarget.className += " active";
    }
  </script>
</body>
</html>

Kết quả

Code này cho kết quả:

Hover vào bất kỳ tab nào: