Logout from Apple Account does not do !

As apple has not provided LOGOUT button it automatically Logout the user after some fixed time or either when user's browser is closed.
I have Apple Safari browser & i have tried opening & closing Safari 3-4 times. I even restarted mah system 2-3 times but it won't work.

I have also done Reset Safari but still i can't log out from Apple Account in Apple Store Website.

Now what should i do now ?
Seeking an urgent help.