Getting a true landscape fullscreen in Safari on iPhone is pretty easy using simple CSS:
html {
height: 100%;
padding-bottom:1px;
}
Then fill the browser window with your pano.
But this doesn't seem to work in the default Android browser nor Chrome or Firefox on Android or iOS phones. The URL bar is always there in Firefox and the status bar in Chrome. Is there a trick to getting real full screen for non-Safari browsers? This seem especially important for WebVR where you really don't want the screen cluttered with such things.