基于数据库的三级菜单实现（二级同理）
<table width="600" border="0" align="center" cellpadding="0" cellspacing="0" class="font">
<tr>
<td height="44" align="right">产品编号:</td>
<td align="left"><input name="pro_id"></td>
</tr>
<tr>
<td height="41" align="right">
<%
set rs=server.CreateObject("adodb.recordset")
sq="select * from pro_big_part"
rs.open sq,conn,1,1%>
<select name="big_part" onChange="ld();ld2()">
<option value="" selected>选择一级目录</option>
<%while not rs.eof%>
<option value="<%=rs("big_part")%>"><%=rs("big_part")%></option>
<%rs.movenext
wend
rs.close%>
</select> </td>
<td align="left"> <select name="small_part" onChange="ld2()">
<option value="" selected>选择二级目录</option>
</select> <select name="thr_part">
<option value="" selected>选择三级目录</option>
</select>
<%sql="select * from pro_small_part"
rs.open sql,conn,1,1
num=rs.recordcount
str=""
for i=1 to rs.recordcount
str=str&rs("big_part")&"-"&rs("small_part")&","
if rs.eof then exit for
rs.movenext
next
rs.close
%>
<%sql="select * from pro_thr_part"
rs.open sql,conn,1,1
num2=rs.recordcount
str2=""
for i=1 to rs.recordcount
str2=str2&rs("small_part")&"-"&rs("thr_part")&","
if rs.eof then exit for
rs.movenext
next
rs.close
%>
<!--下面是实现动态改变下一级菜单的脚本代码-->
<script LANGUAGE="javascript">
arr="<%=str%>".split(",");
a=arr.length
ar=new Array()
for (i=0;i<a;i++){
ar[i]=arr[i].split("-");
}
onecount=ar.length;
arr2="<%=str2%>".split(",");
a2=arr2.length
ar2=new Array()
for (i=0;i<a2;i++){
ar2[i]=arr2[i].split("-");
}
onecount2=ar2.length;
function ld() {
document.form1.small_part.length=0
lid=form1.big_part.value;
for (i=0;i<onecount;i++) {
if (ar[i][0] == lid) {
document.form1.small_part.options.add(new Option(ar[i][1], ar[i][1]));
}
}
}
function ld2() {
document.form1.thr_part.length=0
lid2=form1.small_part.value;
for (i=0;i<onecount2;i++) {
if (ar2[i][0] == lid2) {
document.form1.thr_part.options.add(new Option(ar2[i][1], ar2[i][1]));
}
}
}
</script></td>
</tr></table>