remove cache of webpage

I used Forms Authentication to control accessing webpage. However, when user logs out, user still can access the web page by clicking button "Back" on toolbar of IE.

How can I redirect to login webpage?

Thanks in advance.

I got the answer.

the following code snippet could added into Page_Init function of secured page:

Code:

---

Response.Cache.SetExpires(DateTime.Now)
Response.Cache.SetCacheability(HttpCacheability.NoCache)

---

.

I have one more secured webpage. When I go back from second page to first page while user still logged on, it doesn't work. How can I fix it?

thx in advance.