Selectors/API/jQuery - Sample Code
:header
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<script src="/jquery/js/jquery.js"></script>
<script>
$(document).ready(function(){
$(":header").css({ background:'#CCC', color:'blue' });
});
</script>
</head>
<body>
<h1>ここはヘッダです</h1>
<div>
<p>ここは違います</p>
<h2>ここもヘッダです</h2>
<p>ここは違います</p>
</div>
</body>
</html>
[実行結果]