Phone user cannot scroll to hide browser address bar

• iOS7.1 iPhone5s

When viewing a typical web page, the user can scroll down the page to hide browser bars (the top address bar and the bottom bar).



However, for a Touch web app, presumably because Ext.Viewport always fits the screen exactly, the user is not able to hide browser bars by scrolling content inside the Viewport. It's confusing to the user, because it looks like the page content is scrolling down, but the browser bars do not disappear as expected. It's pretty significant waste of screen real estate on a phone device.



What are the options to let users hide the browser bars or do it programmatically, for a Touch web app? We are looking for solutions working for all major phone/browser versions.



THANKS!