plugins/fullscreen/fullscreen.js
function isFullscreen() {
        return document.fullScreenElement ||
            document.webkitFullscreenElement ||
            document.mozFullScreenElement ||
            document.msFullscreenElement ||
            isFakeFullscreen;
    }
function isFullscreen() {
        return document.fullScreenElement ||
            document.webkitFullscreenElement ||
            document.mozFullScreenElement ||
            document.msFullscreenElement ||
            isFakeFullscreen;
    }
function isFullscreen ( ) { return document . fullScreenElement || document . webkitFullscreenElement || document . mozFullScreenElement || document . msFullscreenElement || isFakeFullscreen ; }
Return true if full screen is active
@returns {boolean}
@private
Return true if full screen is active