ExtJS 4 logout from ExtJS after session is over

[Swipsy]

I use CodeIgniter for my backend and ExtJS 4.1 for the frontend. In a controller in CI I check if an users session is over and if so I perform\[quote\] redirect('login');\[/quote\]However what actually happen is - I stop to get response from the server but my ExtJS is still working and I don't get the loginpage. How can I redirect from ExtJS when I see on the server side that session is over?ThanksLeron