removing navigation bar safari

When the user navigates from the main menu of my hybrid html app this navigation bar always appears on every subsequent html page and pushes the header down. Is there a way to remove the Safari back button and nav bar seen here? I have custom back/forward buttons within the app already for the user to navigate and ideally need to get it fullscreen. I would appreciate any feedback since I have looked everywhere.

My header code on this subpage is: