$(function (){
		
		var itemHeight = 50; /* in pixels */
		var scrollDistance = 3; /* number of stories to scroll through on click */
		var moveDistance = 0;
		var containerHeight = $('.restrainer').height();
		var platterHeight = $('.vertical-scroll-container').height();
		var startScroll = 0;
		var endScroll = platterHeight - containerHeight;

		function resetVisibility(){
			$('.vertical-slider-scroll-up').animate({opacity: 1}, 0);
			$('.vertical-slider-scroll-down').animate({opacity: 1}, 0);
		}

		function scroll(direction){
			var locationUnits = $('.vertical-scroll-container').css("top").length;
			/* get value minus 'px' */
			var location = Number(
				$('.vertical-scroll-container').css("top").slice(0,locationUnits-2)
			);
			
			/* depending on which button what clicked */
			if (direction == 'up'){
			
				if(location < startScroll){
					moveDistance = location + scrollDistance * itemHeight;
					resetVisibility()
				} else {
					$('.vertical-slider-scroll-up').animate({opacity: .1}, 175);
				}
				
			} else if (direction == 'down'){
			
				if(Math.abs(location) < endScroll){
					moveDistance = location - scrollDistance * itemHeight;
					resetVisibility()
				} else {
					$('.vertical-slider-scroll-down').animate({opacity: .1}, 175);
				}

			}

			/* slide the content */
			$('.vertical-scroll-container').animate({ 
				top: moveDistance+'px'
			}, 500);
		}

		/* up button */
		$('.vertical-slider-scroll-up').click(function(){  
			scroll('up');
			return false;
		});

		/* down button */
		$('.vertical-slider-scroll-down').click(function(){  
			scroll('down');
			return false;
		});
		
		// start it up
		$('.vertical-slider-scroll-up').trigger('click')
	});