Read Ben Frain‘s Post The iOS Safari menu bar is hostile to web apps: discuss first!
Whether you're developing a web application with native-ish UI, or just a simple modal popup overlay that covers the viewport, when it comes to making things work on iDevices in Mobile Safari, you're in for a decent amount of pain and suffering. Making something "100% height" is not as easy as it seems.
This post is a collection of Mobile Safari's gotchas and quirks on that topic, some with solutions and fixes, some without, in good parts pulled from various sources across the internets, to have it all in one place. Things discussed here apply to iOS8, iOS9 and iOS10.
Screen real estate on smartphones is limited, so Mobile Safari collapses the browser chrome (address bar and optional tab bar at the top, and tool bar at the bottom) when the user scrolls down. When you