// vertical slider control
			var slider = new Control.Slider('handle', 'scroll_track', {
				axis: 'vertical',
				range: $R(0,50),
				values: [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50],
	                       onSlide: function(v) { scrollVertical(v, $('scrollable_content'), slider);  },
	                       onChange: function(v) { scrollVertical(v, $('scrollable_content'), slider); }
			});

// 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));
			}

             		// mouse wheel code from http://adomas.org/javascript-mouse-wheel/
			function handle(delta) {slider.setValueBy(-delta);}

			/** Event handler for mouse wheel event. */
			function wheel(event){
				var delta = 0;
				if (!event) /* For IE. */
					event = window.event;
				if (event.wheelDelta) { /* IE/Opera. */
					delta = event.wheelDelta/120;
					/** In Opera 9, delta differs in sign as compared to IE. */
					if (window.opera)
						delta = -delta;
				} 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 (delta)
					handle(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('scrollable_content', 'DOMMouseScroll', wheel);
			
			// IE/Opera
			Event.observe('scrollable_content', 'mousewheel', wheel);


        // disable vertical scrolling if not needed
                     var divh = document.getElementById('interior_center').offsetHeight;
                    if (divh <= 563) {
	             document.getElementById('handle').style.visibility = 'hidden';
                    }