public static ScrollSpy scrollSpy(final String selector) {
        return new ScrollSpy((Element) Document.get().getBody().cast(), selector);
    }
public static ScrollSpy scrollSpy ( final String selector ) { return new ScrollSpy ( ( Element ) Document . get ( ) . getBody ( ) . cast ( ) , selector ) ; }
Attaches ScrollSpy to document {@code <body>} and with the specified
target CSS selector.

@param selector CSS selector for target element
@return ScrollSpy