请教一下一般网页正文下面都有上一篇和下一篇文章，请问这是怎么做的

<%
pid1=rs("newsid")
function Getpre
sql="select top 1 * from shop_news1 where newsid>"&pid1&" order by newsid"
set rs=conn.execute(sql)
if rs.eof or rs.bof then
response.Write("没有新闻了")
else
pid2=rs("newsid")
response.Write("<a href='news1.asp?id="&pid2&"'>"&rs("newsname")&"</a>")
end if
end function

function Getnext
sql="select top 1 * from shop_news1 where newsid<"&pid1&" order by newsid desc"
set rs=conn.execute(sql)
if rs.eof then
response.Write("没有新闻了")
else
pid3=rs("newsid")
response.Write("<a href='news1.asp?id="&pid3&"'>"&rs("newsname")&"</a>")
end if
end function
%>

<table width="560" border="0" cellspacing=&