rs为一级栏目的记录集
rs2为二级栏目的记录集
分别替换成你自己的记录集名称就好了
<script language="JavaScript">
var onecount;
var count;
onecount=0;
subcat = new Array();
<%
count = 0
do while not rs2.eof
%>
subcat[<%=count%>]=new Array("<%=trim(rs2("eid"))%>","<%= trim(rs2("elm"))%>","<%= trim(rs2("ssyl"))%>");
<%
count = count + 1
rs2.movenext
loop
rs2.close
%>
onecount=<%=count%>;
function changelocation(locationid)
{
document.form1.elm.length = 0;
document.form1.elm.options[document.form1.elm.length] = new Option("请选择二级栏目", "");
var locationid=locationid;
var i;
for (i=0;i < onecount; i++)
{
if (subcat[i][2] == locationid)
{
document.form1.elm.options[document.form1.elm.length] = new Option(subcat[i][1], subcat[i][0]);
}}}
</script>
<form method="POST" name="form1" action="" onSubmit="">
<table width="960">
<tr>
<td width="571" colspan="3">栏目
<select name="ylm" onChange="changelocation(document.form1.ylm.options[document.form1.ylm.selectedIndex].value)" size="1">
<option selected value="">请选择一级栏目</option>
<%
do while not rs.eof
%>
<option value="<%=trim(rs("yid"))%>"><%=trim(rs("ylm"))%></option>
<%
rs.movenext
loop
rs.close
%>
</select> >> <select name="elm" size="1" onchange="lm_true()">
<option selected value="">请选择二级栏目</option>
</select>
<input type="submit" name="button" id="button" value="提交"/>
</table>
<input runat="server" type="hidden" name="MM_insert" value="form1" />
</form>
http://jingyan.baidu.com/article/eae0782788e9d71fec548590.html