How to find out if video is enabled in full screen in IE

Question

I checked the JavaScript code below to determine if the HTML5 video is in full screen or not. The code worked fine in Chrome, Firefox, and Opera, but not in IE. How to do it in Internet Explorer? I tried "document.msFullscreenElement", but that did not work.

if( document.fullscreenElement || document.webkitFullscreenElement || document.mozFullScreenElement || document.msFullscreenElement || document.oFullscreenElement) mode = "FULLSCREENVIDEO"; else mode = "REGULAR";