You can't. The container knows about himself, his environment, his applications, incoming requests... It doesn't know about the thousand users unix/windows/other account accessing its applications.
You have to make a proper web authentication system in your application to identify your users.
Ok, My requirement is poping up an alert which is
user dependent. I can use cookies for that. But javascript and html page
can not give me user data. How can I do that?
So once a person logs in and opens a browser is there any way to capture
his user id?
I had already told you this in the other post that you opened. Please do not cross-post the same question in multiple forums. It wastes people's time when multiple redundant conversations take place. Please click this link ⇒ CarefullyChooseOneForum ⇐ for more information.