. . . "Also note that the {{ domevent(mozfullscreenchange) }} event does not provide any information itself as to whether the element is entering or exiting full-screen mode, but if the document has a non null {{ domxref(document.mozFullScreenElement, mozFullScreenElement) }}, or if its {{ domxref(document.mozFullScreen, mozFullScreen) }} attribute is true, you know you have entered full-screen mo" .