源码
<!doctype html>
<html>
<head>
<meta name="" content="" charset="utf-8"/>
</head>
<!-- framset标签和body标签不能同时用 -->
<frameset cols="80%, 20%" border="1">
<frame src="part1.html" >
<frame src="part2.html" >
</frameset>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<iframe src="https://bilibili.com" width="100%" height="1200px" name="main_page"></iframe>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
body{
background-color: aqua;
}
</style>
<link rel="stylesheet" type="text/css" href="./css/demo01.css"/>
</head>
<!--Style遵循就近原则-->
<body style="background-color: mediumaquamarine">
<body>
<ul>
<li>
<a href="https://bilibili.com" target="main_page">BILIBILI</a>
</li>
<li>
<a href="https://www.taobao.com/" target="main_page">淘宝</a>
</li>
<li>
<a href="https://qd.58.com/" target="main_page">58同城</a>
</li>
</ul>
</body>
</html>
body{
background-color: saddlebrown;
}
效果