[eluser]web_developer[/eluser]
Thanks for the reply. And I am sorry for my behaviour. My client is getting angry on me and I have shouted here

Still one question. Why CI is not giving something in-built functionality?
As every functionality is operating very wonderful from config file. Then why in CI it has not put 2 type of option?
something like
enable_session_cookie = True/False;
Even it should also required to put in manual of session part. This is the most important thing. Because there are many new users like me, which are learning CI & implementing in their project. And it's not look feasible to check forum for the solution and apply external class,do override, Blah blah...
I hope you understand my point.