Notification bar won't go away.

[coolstory]

I don't know if I just noticed this, but my notification bar at the top of the screen is not going away. I can hide status bar with apps like clash of clans, and the android stock browser. But why I can't do the same on Chrome or Firefox browser? Is it possible to hide status bar on Chrome? It's rather asinine that the notification bar remains to take up valuable space when I'm using internet browsers. I'm on Kitkat. Thanks.