function onProgressClicked( event ) {

		onUserInput( event );

		event.preventDefault();

		var slidesTotal = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
		var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );

		if( config.rtl ) {
			slideIndex = slidesTotal - slideIndex;
		}

		slide( slideIndex );

	}
Clicking on the progress bar results in a navigation to the
closest approximate horizontal slide using this equation:

( clickX / presentationWidth ) * numberOfSlides