interface HTMLElement { webkitRequestFullScreen(options?: FullscreenOptions): Promise mozRequestFullScreen(options?: FullscreenOptions): Promise msRequestFullscreen(options?: FullscreenOptions): Promise } interface Document { webkitFullscreenElement: Element | null mozFullScreenElement: Element | null msFullscreenElement: Element | null webkitCurrentFullScreenElement: Element | null mozCancelFullScreen(): Promise webkitExitFullscreen(): Promise msExitFullscreen(): Promise }