<!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> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title></title> <!-- 引入jQuery --> <script src="../js/jquery-1.4.3.js" type="text/javascript"></script> <script type="text/javascript"> $(function(){ var $s =$("#test>div"); var $t = $("#test div"); alert($s.length);//获取子节点 3 alert($t.length);//获取子节点及其下属的子节点 5 }) </script> </head> <body> <div id="test"> <div id="test1"> <div id="test11"> <div id="test111"> </div> </div> </div> <div id="test2"> </div> <div id="test3"> </div> </div> </body> </html> </span>