if ($('show2scroll') != null) {
	// vertical slider control
	var slider1 = new Control.Slider('handle1', 'track1', {
		axis: 'vertical',
		onSlide: function(v) { scrollVertical(v, $('show2scroll'), slider1);  },
		onChange: function(v) { scrollVertical(v, $('show2scroll'), 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 text doesn't overflow the div
if ($('show2scroll') != null && ($('show2scroll').scrollHeight <= $('show2scroll').offsetHeight)) {
	slider1.setDisabled();
	$('track1').hide();
	$('scrollInstruct').hide();
}