麦秀的网络生活

<%
    dim cid,coid
    cid = request("cid")  'cid   大类id
    coid = request("coid")   'coid  中类id
     set rs=server.createobject("adodb.recordset")  
     sql = "select * from edu_c"    '表一  大类表
     rs.open sql,conn,1,1
     strOption1 = "<option value='' selected >==请选择所属市局==</option>"
           do while not rs.eof
           if cstr(rs("id")) = cstr(cid) then
                 strOption1 = strOption1 & "<option value='" & rs("id") & "' selected>" & rs("c_name") & "</option>"
           else
    
          strOption1 = strOption1 & "<option value='" & rs("id") & "'>" & rs("c_name") & "</option>"
           
     end if
     rs.movenext      
            loop   
 
     rs.close
    
     if cid <> "" then
           sql = "select * from edu_co where c_id=" & cid   '表二  中类表   bid==表一中的id
        
     rs.open sql,conn,1,1
           strOption2 = "<option value='' selected >==请选择所属县局==</option>"
  
           do while not rs.eof
                 if cstr(rs("id")) = cstr(coid) then
                       strOption2 = strOption2 & "<option value='" & rs("id") & "' selected>" & rs("co_name") & "</option>"
                 else
                       strOption2 = strOption2 & "<option value='" & rs("id") & "'>" & rs("co_name") & "</option>"
                 end if
        rs.movenext
           loop
           rs.close
     end if
    
     if coid <> "" then
           sql = "select * from edu_s where co_id= " & coid  '表三   小类表  mid==表二的id
           rs.open sql,conn,1,1
           strOption3 = "<option value='' selected >==请选择学校==</option>"
           while not rs.eof
           if cstr(rs("id")) = cstr(sid) then
                       strOption3 = strOption3 & "<option value='" & rs("id") & "' selected>" & rs("s_name") & "</option>"
                 else
                       strOption3 = strOption3 & "<option value='" & rs("id") & "'>" & rs("s_name") & "</option>"
                 end if
         
           rs.movenext
           wend
     rs.close
     end if
    
%>
<select onchange="changeb(this.value)" name="cid"><%=strOption1%></select>
<select onchange="change(this.value)" name="coid"><%=strOption2%></select>
<select name="sid"><%=strOption3%></select>
<script language="javascript">
<!--
     function changeb(cid){
           location.assign("three.asp?action=s_s&cid=" + cid);  
     }
    
     function change(coid){
           location.assign("three.asp?action=s_s&cid=<%=cid%>&coid=" + coid);   
     }
-->
</script>

<%'＝＝＝＝＝＝＝＝
上面给出的是三级联动菜单，思路如此清晰，四级，多级联动菜单的制作一一类推就明白，作者的程序清晰明了，一看就明白了。
＝＝＝＝＝＝%>