export interface ViewportOffsetResult {
    left: number;
    top: number;
    right: number;
    bottom: number;
    rightIncludeBody: number;
    bottomIncludeBody: number;
}
export declare function getBoundingClientRect(element: Element): DOMRect | number;
export declare function hasClass(el: Element, cls: string): boolean;
export declare function addClass(el: Element, cls: string): void;
export declare function removeClass(el: Element, cls: string): void;
export declare function getViewportOffset(element: Element): ViewportOffsetResult;
export declare function hackCss(attr: string, value: string): any;
export declare function on(element: Element | HTMLElement | Document | Window, event: string, handler: EventListenerOrEventListenerObject): void;
export declare function off(element: Element | HTMLElement | Document | Window, event: string, handler: EventListenerOrEventListenerObject): void;
export declare function once(el: HTMLElement, event: string, fn: EventListener): void;