$(document).ready(function(){
	$('.scroller').each(function(){
		$(this).css('position','relative').parent().attr('rel',1);
		
		var h = parseInt($(this).css('height'));
		$('.element',this).each(function(i){
			$(this).css('height',h).css('position','absolute').css('top',i*h+'px');
		});
		
		if($('.element',this).length <= 1) $('.slide_down',$(this).parent()).css('visibility','hidden');
	});
	
	//nascondo tutte le frecce in alto
	$('.slide_up').css('visibility','hidden');
	
	$('.slide_down').click(function(e) {
		e.preventDefault();
		
		var box = $(this).parent();				
		var h = parseInt($('.scroller',box).css('height'));
		
		$('.element',box).animate({'top':'-='+h+'px'});
		$('.slide_up',box).css('visibility','visible');	

		var current = parseInt($(box).attr('rel'));
		$(box).attr('rel',++current);
		
		if(current == $('.element',box).length) $('.slide_down',box).css('visibility','hidden');	

	});

	$('.slide_up').click(function(e) {
		e.preventDefault();
					
		var box = $(this).parent();
		var h = parseInt($('.scroller',box).css('height'));
		
		$('.element',box).animate({'top':'+='+h+'px'});
		$('.slide_down',box).css('visibility','visible');
		
		var current = parseInt($(box).attr('rel'));
		$(box).attr('rel',--current);
		
		if(current == 1) $('.slide_up',box).css('visibility','hidden');	
		
	});

	
});