获取某个指定元素下面的子元素可以用
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<style>
 body { font-size:16px; font-weight:bolder; }
 p { margin:5px 0; }
</style>
</head>
<body>
 <div class="test">
   <span>Hello</span>
   <p id="1" class="selected">Hello Again</p>
   <div class="selected">And Again</div>
   <p id="2">And One Last Time</p>
 </div>
<script>$(".test").children("p").css("color", "red");
var test=$(".test").children("p");
test.each(function(){
     alert($(this).attr("id"))
   })
</script>
</body>
</html>

获取到的现在是个对象，还不能用，要循环出来才可用

<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
 $("button").click(function(){
   $("li").each(function(){
     alert($(this).text())
   });
 });
});
</script>
</head>
<body>
<button>输出每个列表项的值</button>
<ul>
<li>Coffee</li>
<li>Milk</li>
<li>Soda</li>
</ul>
</body>

</html>

JQ追加元素用 $("#ol_"+replyid).append("<li>fdgdf</li>"); 即可