close current browser tab in asp.net without using javascrip

You cant do it using serverside code. you have to do it using javascript only
this code will work in ie but some problem in firefox because the

script is not allowed to close browser in Firefox for that you have to change some values in firefox about.config file.

please set your firefox browser:

1.input "about:config " to your firefox address bar and enter;

2.make sure your "dom.allow_scripts_to_close_windows" is true

and check