ASP unlimited grading (recursive call)

Database field: ID (automatic number), class_name (menu name), parentid (parent menu ID) CopyCode The Code is as follows: <%
Dim m
M = 0
Call showtree (0) %>
<%
Sub showtree (parentid)
Dim s
M = m + 1
Dim rs
Set rs = server. Createobject ("ADODB. recordset ")
SQL = "select class_id, class_name from [wms_class] Where class_father_id =" & CINT (parentid)
Rs. Open SQL, Conn, 1, 1
If Rs. EOF and M = 1 then
Response. Write ("this channel has no topic ")
End if
Do while not Rs. EOF
Response. Write RS (0)
For n = 1 to m
If n = M and M = 1 then
Response. Write ("response ")
Elseif n = 1 then
Response. Write ("")
Elseif n = m then
Response. Write ("response ")
Else
Response. Write ("│ ")
End if
Next
Response. Write RS (1) & "<br>"
Call showtree (RS (0 ))
M = S-1
Rs. movenext
Loop
End sub
%>