hierarchy navigation back button in asp.net

[fer3d]

I need to implement a back button for my asp application. In my web application I got 3 module [*]task1.aspx ->task1-1.aspx ->task1-2.aspx[*]task2.aspx-> task2-1.aspx->task3-1.aspx[*]task3.aspx->task3-1.aspx->task2.1aspxIn the above example.3 module also can navigate to other pages . So now I got problem, is it possible to implement a back button based on which previous page that I come from.For example, I clicktask3.aspx -> task3-1.aspx -> task2.1aspx then when I click back button, will betask2.1aspx -> task3-1.aspx -> task3.aspx. On the other hand, when I click task2.aspx -> task2-1.aspx.the back button will navigate me to task2-1.aspx ->task2.apxIs it possible done in server side? thanks