跪求展开树型结构后焦点获得问题思路

我使用的是jenkov的treetag标签
当我展开树型菜单的时候，怎么可以让我展开的这个文件获得焦点（焦点这词不知道准确与否，意思就是当我点击展开一个树形菜单，我就是显示在我展开的这个菜单上），而不是刷新后显示树形菜单的起始部分。
雪地跪求思路。附上JSP页面源码。
<%@ page contentType="text/html;charset=GB2312"%>
<%@ include file = "../users/CheckSession.jsp"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ taglib uri="/WEB-INF/treetag.tld" prefix="tree" %>
<%@ taglib uri="/WEB-INF/requesttags.tld" prefix="request" %>
<%@ page import="bussiness.role.RoleDao"%>
<%@ page import="com.jenkov.prizetags.tree.itf.*"%>
<% 
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path;
%>
<%
    if(session.getAttribute("IAppTree") == null){
RoleDao dao = new RoleDao();
ITree tree = dao.getRoleAppTree((String)session.getAttribute("roleId"));  
session.setAttribute("IAppTree",tree);
}
%><html>
<head>
<link rel="stylesheet" type="text/css" href="../css/style.css">
<tree:onSelect>
<script>
  var url = '<tree:selectedNodeId/>';
  window.open('<%=request.getContextPath()%>/a.jsp?url='+url,"mainFrame", "");
</script>
</tree:onSelect>
<link href="../styles/login.css" type="text/css" rel="stylesheet">
<link href="../styles/style.css" type="text/css" rel="stylesheet">
 <link rel="stylesheet" type="text/css" href="../css/default.css"> </head>
<body style="background-color:#e7f3ff;font-family:Arial;" style="background-image:url(../images/index-left02.gif); background-repeat:repeat-y;">
<table cellspacing="0" cellpadding="0" style="border: none;" class="table-style">
<tr>
 <td>
        <table cellspacing="0" cellpadding="0" border="0" >
        <tree:tree tree="IAppTree" node="IAppTree.node" includeRootNode="false">
            <tr><td >
             <table cellspacing="0" cellpadding="0" border="0">
            <tr> 
            <td>&nbsp;</td>
            <td>&nbsp;</td>
             <td>
             <tree:nodeIndent node="IAppTree.node" indentationType="type">
             <tree:nodeIndentVerticalLine indentationType="type" ><img src="../jsp/treeimages/verticalLine.gif"></tree:nodeIndentVerticalLine>
             <tree:nodeIndentBlankSpace   indentationType="type" ><img src="../jsp/treeimages/blankSpace.gif"></tree:nodeIndentBlankSpace>
             </tree:nodeIndent>
             </td>
             <tree:nodeMatch node="IAppTree.node" expanded="false" hasChildren="true"  isLastChild="false">
             <td><a href="<request:requestUri/>?expand=<tree:nodeId node="IAppTree.node"/>"><img src="../jsp/treeimages/collapsedMidNode.gif" border="0"></a><img src="../jsp/treeimages/folder.gif" class="img-floder"></td>
             </tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" expanded="true"  hasChildren="true"  isLastChild="false"><td><a href="<request:requestUri/>?collapse=<tree:nodeId node="IAppTree.node"/>"><img src="../jsp/treeimages/expandedMidNode.gif"  border="0"></a><img src="../jsp/treeimages/folderopen.gif" class="img-floder"></td></tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" expanded="false" hasChildren="true"  isLastChild="true" ><td><a href="<request:requestUri/>?expand=<tree:nodeId node="IAppTree.node"/>"><img src="../jsp/treeimages/collapsedLastNode.gif"  border="0"></a><img src="../jsp/treeimages/folder.gif" class="img-floder"></td></tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" expanded="true"  hasChildren="true"  isLastChild="true" ><td><a href="<request:requestUri/>?collapse=<tree:nodeId node="IAppTree.node"/>"><img src="../jsp/treeimages/expandedLastNode.gif" border="0"></a><img src="../jsp/treeimages/folderopen.gif" class="img-floder"></td></tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" expanded="false" hasChildren="false" isLastChild="false"><td><img src="../jsp/treeimages/noChildrenMidNode.gif"><img src="../jsp/treeimages/button3.gif" class="img-floder"></td></tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" expanded="false" hasChildren="false" isLastChild="true" ><td><img src="../jsp/treeimages/noChildrenLastNode.gif"><img src="../jsp/treeimages/button3.gif" class="img-floder"></td></tree:nodeMatch>
            <td valign="middle" nowrap>
            <tree:nodeMatch node="IAppTree.node" selected="true"><a href="<request:requestUri/>?select=<tree:nodeId node="IAppTree.node"/>" >&nbsp;<font face="Arial"><tree:nodeName node="IAppTree.node" /></font></a></tree:nodeMatch>
            <tree:nodeMatch node="IAppTree.node" selected="false"><a href="<request:requestUri/>?select=<tree:nodeId node="IAppTree.node"/>">&nbsp;<font face="Arial"><tree:nodeName node="IAppTree.node"/></font></a></tree:nodeMatch>
            </td>
          </tr>             
</table>
        </td></tr>
    </tree:tree>
   </table>
</td></tr>
</table></body>
</html>