function update($slider, $offset)
{
	if (!isNaN($offset)) $slider.slider('value', $slider.slider('value') + (-$offset * 10));

	$position = (100 - $slider.slider('value')) / 100;
	$container = $('#builders .content');
	$limit = $container.height();
	$items = $container.find('.scrollable');
	$items.css('marginTop', -$position * Math.max(0, $items.height() - $limit));
}


$().ready(function() {
	$('#builders').opacity(0.87); 
			
	$slider = $('#builders .scrollbar .track');
	$slider.slider({ orientation: 'vertical', min: 0, max: 100, value: 100, animate: true });
	$slider.bind('slidechange slide', function() { update($(this)); });

	$('#builders .scrollbar .button1, #builders .scrollbar .button2').bind('mousedown', function() {
		$slider = $(this).closest('.scrollbar').find('.track');
		update($slider, ($(this).attr('class') == 'button1' ? -1 : 1));
	});
});