<!DOCTYPE html>
<html>
<head>
<title>ance desc选择器</title>
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js" type="text/javascript"></script>
</head>
<body>
<div>码农家族
<p>
<label></label>
<li></li>
</p>
<label></label>
</div>
</body>
<script type="text/javascript">
$("p li").css("background-color","blue");
</script>
</html>
想选这p 元素下的li 怎么这样选不到