如何选择二级分类

[chjin]

有二个下拉列表框,选择大类之后,再从后面一个下拉列表框中选择那个大类里的小类,

代码该如何实现?

谢谢各位高人

[chjin]

而且下接列表框中的数据都是在数据库里的.

[sy_binbin]

<script>
<!--
<%
'二级数据保存到数组
Dim count1,cityRS,citySQL
set cityRS=server.createobject("adodb.recordset")
citySQL="select * from city order by shiorder"
cityRS.open citySQL,conn,1,1
%>
var subval2 = new Array();
//数组结构：一级根值,二级根值,二级显示值
<%
count1 = 0
do while not cityRS.eof
%>
subval2[<%=count1%>] = new Array('<%=cityRS("Shengid")%>','<%=cityRS("id")%>','<%=cityRS("shiname")%>')
<%
count1 = count1 + 1
cityRS.movenext
loop
cityRS.close
%>
function changeselect1(locationid)
{
document.form1.city.length = 0;
document.form1.city.options[0] = new Option('请选择城市','');
for (i=0; i<subval2.length; i++)
{
if (subval2[i][0] == locationid)
{document.form1.city.options[document.form1.city.length] = new Option(subval2[i][2],subval2[i][1]);}
}
}
//-->
</script>
<form action="" method="post" name="form1" >
<select name="province" class="buttonmain" id="province" onChange="changeselect1(this.value)">
<option value="">请选择省份</option>
<%
dim provinceRS,provinceSQL
set provinceRS = server.createobject("adodb.recordset")
provinceSQL = "select * from province order by shengorder"
provinceRS.open provinceSQL,conn,1,1
do while not provinceRS.eof
response.Write "<option value="&provinceRS("id")&">"&provinceRS("shengname")&"</option>"

provinceRS.movenext
loop
provinceRS.close
set provinceRS = nothing
%>
</select>
<select name="city" class="buttonmain" id="city">
<option value="">请选择城市</option>
</select>
</form>

[chjin]

请帮我看看,那里错了,为什么选了大类之后,小类不会更新:

<script>
<%
'二级数据保存到数组
set rs=server.createobject("adodb.recordset")
sql="select * from p_smallclass order by c_id asc"
rs.open sql,conn,1,1
%>
var subval2 = new Array();
//数组结构：一级值,二级值
<%
count1 = 0
do while not rs.eof
%>
smallclass[<%=count1%>][0] =('<%=rs("c_big")%>')
smallclass[<%=count1%>][1] =('<%=rs("c_name")%>')
<%
count1 = count1 + 1
rs.movenext
loop
rs.close
%>
function changesmall(bigclass)
{
document.faddcp.fsmallclass.length = 0;
document.faddcp.fsmallclass.options[0] = new Option('请选择产品所属大11类');
for (i=0; i <smallclass.length; i++)
{
if (smallclass[i][0] == bigclass)
{document.faddcp.fsmallclass.options[document.faddcp.fsmallclass.length] = new Option(smallclass[i][1];}
}
}
</script>
<link href="admin.css" type=text/css rel=stylesheet>
<form name="faddcp" id='faddcp' method="post" action="addcp.asp" onsubmit="return check()">
<select name="fbigclass" onChange="changesmall(this.value)">
<option value="">请选择产品所属大类</option>
<%
set rs = server.createobject("adodb.recordset")
sql = "select * from p_bigclass order by c_id asc"
rs.open sql,conn,1,1
do while not rs.eof%>
<option value="<%=rs("c_name")%>"><%=rs("c_name")%></option>
<%rs.movenext
loop
rs.close
set rs=nothing
%>
</select>
<select name="fsmallclass" id="fsmallclass">
<option value="">请选择产品所属小类</option>
</select>
</form>

[chjin]

原来是少了一个),唉.