:header Selector
header selector
version added: 1.2jQuery(':header')
描述： 选择所有标题元素，像h1, h2, h3 等.
Example:
Adds a background and text color to all the headers on the page.
<!DOCTYPE html>
<html>
<head>
<style>
body { font-size: 10px; font-family: Arial; }
h1, h2 { margin: 3px 0; }
</style>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
</head>
<body>
<h1>Header 1</h1>
<p>Contents 1</p>
<h2>Header 2</h2>
<p>Contents 2</p>
<script>$(":header").css({ background:'#CCC', color:'blue' });</script>
</body>
</html>