var slider1 = new Control.Slider('handle', 'track_slideshow', {
	axis: 'vertical',
	onSlide: function(v) { scrollVertical(v, $('content_scrollable_slideshow'), slider1);  },
	onChange: function(v) { scrollVertical(v, $('content_scrollable_slideshow'), slider1); }
			});
			
// scroll the element vertically based on its height and the slider maximum value
	function scrollVertical(value, element, slider) {
	element.scrollTop = Math.round(value/slider.maximum*(element.scrollHeight-element.offsetHeight));
			}
			
// disable vertical scrolling if not needed
	if ($('content_scrollable_slideshow').scrollHeight <= $('content_scrollable_slideshow').offsetHeight) {
	slider1.setDisabled();
	$('track_slideshow').hide();
	$('more_slideshow').hide();
			}