<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<meta charset="utf-8" />
<script src="jquery-3.3.1.js"></script>
<script>
$(function () {
$('#btn').click(function () {
$(':header').css('backgroundColor', 'yellow');
});
});
</script>
</head>
<body>
<input type="button" name="name" value="btn" id="btn"/>
<h1>标题</h1>
<h2>标题</h2>
<h3>标题</h3>
<h4>标题</h4>
<h5>标题</h5>
<h6>标题</h6>
</body>
</html>