export declare function isPageVisibilityApiSupported(): boolean;
export declare function isPageHidden(): boolean;
export declare function addPageVisibilityChangedEventListener(visibilityChangedListener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
export declare function removePageVisibilityChangedEventListener(visibilityChangedListener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;