<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- 引入jQuery -->
<script src="../../scripts/jquery-1.3.1.js" type="text/javascript"></script>
<script type="text/javascript">
$(function(){
//注意区分类似这样的选择器
//虽然一个空格，却截然不同的效果.
var $t_a = $('.test :hidden');
var $t_b = $('.test:hidden');
var len_a = $t_a.length;
var len_b = $t_b.length;
alert("$('.test :hidden') = "+len_a); //输出 3 , 即选择所有子孙
alert("$('.test:hidden') = "+len_b); //输出1，只选择对象本身
})
</script>
</head>
<body>
<div class="test">
<p style="display:none;">aa</p>
<div style="display:none;">bb
<div class="test" style="display:none"></div>
</div>
</div>
</body>
</html>
