1.index.html,通過修改link的href屬性來改變主題樣式
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<link id="link" rel="stylesheet" href="./css/css1.css" />
</head>
<body>
<div id="dv" class="box">hello</div>
<input type="button" onclick="document.getElementById('link').href='./css/css2.css'" value="css2" />
<input type="button" onclick="document.getElementById('link').href='./css/css1.css'" value="css1" />
</body>
</html>
2 css1.css
.box{
width: 200px;
height: 200px;
background-color: green;
}
3 css2.css
.box{
height: 100px;
width: 100px;
background-color: grey;
}