How to restrict user from logout when clicking the back button

[Ragesh R pillai]

After successful login when clicking on the  browser back button its getting redirect to login page . how to restrict this.

I don't want to logout the session when clicking the back button. logout should happne only when clicking the log out button.

Any one please help on this. 

 does it can be handle by using  js method

window.onpopstate = function()