【tag_name】
<html>
<head>
<script type="text/javascript" src='http://code.jquery.com/jquery-1.5.2.js'></script>
<script type="text/javascript">
$(document).ready(function(){
$(":header").css({ background:'#CCC', color:'blue' });
});
</script>
</head>
<body>
<h1>Header 1</h1>
<p>Contents 1</p>
<h2>Header 2</h2>
<p>Contents 2</p>
</body>
</html>
