在网上要搜索到相关的资料，知道多级下拉选择框htm的方式是可以实现的，大多是通过数组的方式。
但现在是要实现三级下拉选择框，如：
选第一个下拉选择框的中国，第二个下拉选择框就显示省，再选择省第三个下拉选择框就显示市。
纯文本的例子如下所示：
0755i.com/js/browser/select/preview.htm里边的数据都是从后台数据库里读取。
主要是要从数据库里读取。
不知道ASP如何实现。
有哪位知道。
谢谢了。
下面的代码是否可用呢：
<%@ Language=VBScript %>
<%Option Explicit%>
<html>
<head>
<title>List</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<%
dim conn
dim rs
dim sql
dim count
dim rs1
dim sql1
set conn = server.CreateObject ("adodb.connection"
conn.Open "test","sa",""
sql = "select * from district order by locationid asc"
set rs = conn.execute(sql)
%>
<script language = "javascript">
var onecount;
onecount=0;
subcat = new Array();
<%
count = 0
do while not rs.eof
%>
subcat[<%=count%>] = new Array("<%= trim(rs("districtname"
)%>","<%= trim(rs("locationid"
)%>","<%= trim(rs("districtid"
)%>"
;
<%
count = count + 1
rs.movenext
loop
rs.close
set rs=nothing
%>
onecount=<%=count%>;
function changelocation(locationid)
{
document.myform.smalllocation.length = 0;
var locationid=locationid;
var i;
document.myform.smalllocation.options[0] = new Option('====所有地区====','');
for (i=0;i < onecount; i++)
{
if (subcat[i][1] == locationid)
{
document.myform.smalllocation.options[document.myform.smalllocation.length] = new Option(subcat[i][0], subcat[i][2]);
}
}
}
</script>
</head>
<body>
<form name="myform" method="post">
<select name="biglocation" onChange="changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value)">
<%
sql1 = "select * from location order by locationname asc"
set rs1 = conn.Execute (sql1)
do while not rs1.eof
%>
<option value="<%=trim(rs1("locationid"
)%>"><%=trim(rs1("locationname"
)%></option>
<%
rs1.movenext
loop
rs1.close
set rs1 = nothing
conn.Close
set conn = nothing
%>
</select>
<select name="smalllocation">
<option selected value="">==所有地区==</option>
</select>
</form>
<script LANGUAGE="javascript">
changelocation(document.myform.biglocation.options[document.myform.biglocation.selectedIndex].value);
</script>
</body>
</html>
数据库：
create table location
(
locationid char(2) not null primary key,
locationname char(50) not null
)
create table district
(
districtid char(3) not null primary key,
districtname char(50) not null,
locationid char(2) not null
)
