Validate Login using jQuery or Javascript

Hi

I have wired problem, I have one web site, which is developed using HTML and jQuery.

Flow of Web site:

1) There is one login page. when user entered username and password ajax event call and if user validate user will redirect to home page and users are allows to nevigate throwout the site.

2) Page data will bve filled using ajax request after page is loaded

3) If user logout from site. it will redirect to login page.

Now Problem is when user press browse back botton, user will be redirect to last page and user can nevegate all page.

How CAN i restrict to user?? after logout user can not browse any page. when user are trying to browse page it will redirect to login page.

Thanks in advance