<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="Generator" content="EditPlus?">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<title>css标签选择器</title>
<style type="text/css">
h2{width: 200px;height: 300px;border: 1px solid red; text-align: center;}
</style>
</head>
<body>
<h1>1</h1>
<h2>2</h2>
<h3>3</h3>
<h4>4</h4>
</body>
</html>
原文：http://www.cnblogs.com/caicai2480/p/6379844.html