jsp+javascript打造级连菜单

<%@ page import="java.util.Date,yava.fileapp.*,java.sql.*;"
         contentType="text/html;charset=GB2312" pageEncoding="GB2312"
%>
<style>
.f9{ font-size:9pt; }
.bgc{ background-color:#AECAF9; color: #0033FF }
.buttons{font-family:Arial; font-size:13px; font-weight:bold; background-color:#6796E4; color:white; border-top: solid 2px #AACAFB;
  border-bottom: solid 1px #4E7DC1;
  border-left: solid 1px #AECAF9;
  border-right: solid 1px #5679BD;
  padding:1px;
  margin:0px;}
</style>
<SCRIPT LANGUAGE="JavaScript">
<!--
function rv()
{
  var val="";
  for(i=0;i<combo_box.list2.length;i++){
   val+=","+combo_box.list2[i].value;
  }
  if(val.charAt(0)==","){
   val=val.substr(1,val.length);
  }
  opener.form1.frecname.value=val;
  self.close();
}