<!--#include file=conn.asp-->
<%
dim username,password
if request("username")="" or request("password")="" then
response.write "<script language=javascript>alert('对不起未输入用户名或密码,请返回');history.back(-1)</script>"
end if
dim rs,sql
set rs=server.createobject("adodb.recordset")
sql="select username,password from user username='"&username&"'"
rs.open sql,conn,1,3
if rs.bof and rs.eof then
    response.write "<script language=javascript>alert('帐号未注册');history.back(-1)</script>"
    end if
rs.close
%>

提示说 rs.open sql,conn,1,3这句语法错误，请问应该怎么写才对？！

谢谢~~现在我改了一下~~
<!--#include file=conn.asp-->
<%
dim username,password
if request("username"="" or request("password"="" then
response.write "<script language=javascript>alert('对不起未输入用户名或密码,请返回');history.back(-1)</script>"
else
username=request("username"
password=request("password"
end if
dim rs,sql
set rs=server.createobject("adodb.recordset"
sql="select username,password from [user] where username='"&username&"'"
rs.open sql,conn,1,3
if rs.bof and rs.eof then
response.write "<script language=javascript>alert('帐号未注册');history.back(-1)</script>"
end if
rs.close
Set rs = Nothing
conn.close
set conn=Nothing
%>
可是现在报“至少一个参数没有被指定值”，是不是我还有那里遗漏了？