 update every second
					setInterval( _updateTimer, 1000 );

					function _resetTimer() {

						if (timings == null) {
							start = new Date();
						}
						else {
							// Reset timer to beginning of current slide
							var slideEndTiming = getTimeAllocated(timings) * 1000;
							var currentSlide = Reveal.getSlidePastCount();
							var currentSlideTiming = timings[currentSlide] * 1000;
							var previousSlidesTiming = slideEndTiming - currentSlideTiming;
							var now = new Date();
							start