I\'ve got a web page for the iPhone that uses the HTML5 video tags. On the iPhone, such embedded videos are played in the native player. I wanted to check when the video had end
This is what you need:
yourplayer.addEventListener('webkitendfullscreen', onPlayerExitFullscreen, false);
And vice versa
yourplayer.addEventListener('webkitbeginfullscreen', onPlayerEnterFullscreen, false);
Here's another answer to your question that I found: How to figure out when a HTML5 video player enters the full screen mode on iOS / iPads?