dim username,password
username=session("user")
password=session("pwd")
if reqeust("id")<>username then
response.write "<script>alert('非法操作');window.location.href='index.asp';</script>"
response.end
end if
set rs=conn.execute("select * from [user] where name='"&reqeust("id")&"' and pwd='"&password&"'")
if rs.eof then
response.redirect "login.asp"
else
...
end if
rs.close

asp判断用户是否登陆