window.onload = function() {
		if (document.getElementById('contentscroll')){
				
			if ($('contentscroll').scrollHeight > $('contentscroll').offsetHeight) {
				Element.setStyle('track1', { visibility: 'visible' } );
				Element.setStyle('handle1', { visibility: 'visible' } );
				var sh = Math.ceil($('contentscroll').offsetHeight/$('contentscroll').scrollHeight*$('track1').getHeight());
				var aY = Math.ceil((sh-$('handle1').getHeight())/2);
			} else {
				var aY = 0;
			}
			// vertical slider control
			slider1 = new Control.Slider('handle1', 'track1', {
				alignY: eval(aY),
				axis: 'vertical',
				onSlide: function(v) { scrollVertical(v, $('contentscroll'), slider1);  },
				onChange: function(v) { scrollVertical(v, $('contentscroll'), slider1); }
			});
			

			// scroll the element vertically based on its width 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 text doesn't overflow the div
			if ($('contentscroll').scrollHeight <= $('contentscroll').offsetHeight) {
				slider1.setDisabled();
				$('track1').hide();
			} else {
				Element.setStyle('handle1', { height: sh+'px' } );
				$('arrow_up').show();
				$('arrow_down').show();
			}
			
			Event.observe('arrow_up', 'mousedown', scrollUp);
			Event.observe('arrow_down', 'mousedown', scrollDown);
			
			Event.observe('arrow_down', 'mouseout', function() { if(typeof t=="undefined") {} else { window.clearInterval(t) } });
			Event.observe('arrow_down', 'mouseup', function() { if(typeof t=="undefined") {} else { window.clearInterval(t) }  });
			Event.observe('arrow_up', 'mouseout', function() { if(typeof t=="undefined") {} else { window.clearInterval(t) }  });
			Event.observe('arrow_up', 'mouseup', function() { if(typeof t=="undefined") {} else { window.clearInterval(t) }  });
			
			// mouse wheel code from http://adomas.org/javascript-mouse-wheel/
			function handle(event,delta) {
				var elt = Event.element(event);
				while(elt != $('contentscroll') ) {
					elt = elt.parentNode;
				}
				if(elt == $('contentscroll')){
					slider1.setValueBy(-delta/(elt.scrollHeight-elt.offsetHeight)*20);
				} 
			}
			
			function scrollUp() {
				if(Event.element(event).id == 'arrow_up'){
					var slider = slider1;
				} else {
					var slider = slider1_left;
				}
				t = window.setInterval(function() { slider.setValueBy(-0.1) },100);
			}
			
			function scrollDown() {
				if(Event.element(event).id == 'arrow_down'){
					var slider = slider1;
				} else {
					var slider = slider1_left;
				}
				t = window.setInterval(function() { slider.setValueBy(0.1) },100);
			}

			/** Event handler for mouse wheel event. */
			function wheel(event){
				var delta = 0;
					if (!event) /* For IE. */
						event = window.event;
					if (event.wheelDelta) { /* IE/Opera/Safari. */
						delta = event.wheelDelta/60;
						/** In Opera 9, delta differs in sign as compared to IE. */
						
					} else if (event.detail) { /** Mozilla case. */
						/** In Mozilla, sign of delta is different than in IE.
						* Also, delta is multiple of 3.
						*/
						delta = -event.detail/3;
					}
					/** If delta is nonzero, handle it.
					* Basically, delta is now positive if wheel was scrolled up,
					* and negative, if wheel was scrolled down.
					*/
					if (event,delta)
						handle(event,delta);
						
					
		
					/** Prevent default actions caused by mouse wheel.
					* That might be ugly, but we handle scrolls somehow
					* anyway, so don't bother here..
					*/
					if (event.preventDefault)
						event.preventDefault();
				
					event.returnValue = false;
			}

			// mozilla
			Event.observe('contentscroll', 'DOMMouseScroll', wheel);
			// IE/Opera
			Event.observe('contentscroll', 'mousewheel', wheel);
		}

}