怎样用VBScript实现这个简单的日历？（有效果图）

<%
date_time=trim(request("date_time"))
if date_time="" then date_time=date()
if isdate(date_time)=false then
response.write date_time&"为非法日期格式！！"
response.end
end if
'显示日历开始
r_year=year(date_time)
r_month=month(date_time)
r_day=day(date_time)
response.write "<table width=200 border=1 cellspacing=0 cellpadding=1>"
response.write "<tr align=center><td colspan=7><a href=admin_index.asp?date_time="&dateadd("m",-1,date_time)&"><--</a>  "&formatdatetime(date_time,1)&"  <a href=admin_index.asp?date_time="&dateadd("m",1,date_time)&">--></a></td></tr><tr align=center><td>日</td><td>一</td><td>二</td><td>三</td>&l