Question

asp如何在后台判断前台发来的验证码

前台发送生成的验证码名字位yanzheng
在后台的判断如下
<!--#include file="dbconn.asp"-->

<%
get1=request.Form("NA1")
get2=request.Form("pwd1")
get3=request.Form("yanzheng")
Set rs=Server.CreateObject("ADODB.RecordSet")
sql="select * from manage where NA='"&get1&"'"
rs.open sql,conn,1,1
if rs.bof then
response.redirect("http://www.baidu.com/")
elseif get2<>rs("pwd") then
response.write "<script language=javascript>alert('密码错误');this.location.href='login.asp';</script>"
elseif get1="" or get2="" then
response.write "<script language=javascript>alert('请输入用户名或密码');this.location.href='login.asp';</script>"
elseif get3="" then
response.write "<script language=javascript>alert('验证码不能为空');this.location.href='login.asp';</script>"
else
session("MyName")=rs("NA")
session("MyID")=rs("ID")
session("Mypwd")=rs("pwd")

response.Redirect("ManageIndex.asp")
end if
%>

我这里只判断了代码不能为空 该如何判断是否是前台所产生的代码呢

Answer 1

get1=request.Form("NA1")
get2=request.Form("pwd1")
get3=request.Form("yanzheng")
if get1="" then
response.Write("<script language=javascript>alert('用户名不能为空!');history.go(-1)</script>")
response.end
end if
if get2="" then
response.Write("<script language=javascript>alert('密码不能为空!');history.go(-1)</script>")
response.end
end if
if get3="" then
response.Write("<script language=javascript>alert('验证码不能为空!');history.go(-1)</script>")
response.end
end if
if cstr(Session("GetCode"))<>cstr(Request.Form("Code")) then
response.Write("<script language=javascript>alert('验证码错误!');history.go(-1)</script>")
response.End
end if
sql="..........................'"
set rs...............
if rs.eof or rs.bof then
response.write "<script language=javascript>"
response.write "alert('帐号密码错误，请重新输入!');"
response.write "javascript:history.go(-1);"
response.write "</script>"
else
session.Timeout = 999
session("MyName")=rs("NA")
session("MyID")=rs("ID")
session("Mypwd")=rs("pwd")
response.Redirect("ManageIndex.asp")
end if

验证码应该已经传过来了,你后台还没接收

Answer 2

这个验证码已经是从前台提交过来的了吧，验证码验证正确与否，一般是通过session吧，验证码显示的时候已经写了session，判断与输入是否相符即可。

Answer 3

这个 用的是什么?是图片还是随机数？？