Ciao asva,

lo devi fare in VBScript o in JScript?
Per non sbagliare te faccio 2 esempi
codice:
<%@ Language=VBScript %>
<%
strData = "27/07/2005"
itdate = "^(0[1-9]|[12]\d|3[01])[\/](1[0-2]|0[1-9])[\/]((20)\d{2})$"
set re = Server.CreateObject("VBScript.RegExp")
re.Pattern=itdate
if re.Test(strData) then
  Response.Write "data corretta"
else
  Response.Write "data errata"
end if
%>
codice:
<%@ Language=JScript %>
<%
strData = "27/07/2005"
itdate = /^(0[1-9]|[12]\d|3[01])[\/](1[0-2]|0[1-9])[\/]((20)\d{2})$/
if(itdate.test(strData))
  Response.Write("data corretta")
else
  Response.Write("data errata")
%>