From http://www.w3schools.com (Copyright Refsnes Data)

ASP Expires Property

Response Object Reference Complete Response Object Reference

The Expires property sets how long (in minutes) a page will be cached on a browser before it expires. If a user returns to the same page before it expires, the cached version is displayed.

Syntax

response.Expires[=number]

Parameter Description
number The time in minutes before the page expires

Examples

Example 1

The following code indicates that the page will never be cached:

<%response.Expires=-1%>

Example 2

The following code indicates that the page will expire after 1440 minutes (24 hours):

<%response.Expires=1440%>

Response Object Reference Complete Response Object Reference

From http://www.w3schools.com (Copyright Refsnes Data)