var page = {};
var total_pages = {};

function move_left(which, element)
{
	if(page[which] == 1) return;
	
    new Effect.MoveBy($('photos_' + which).childNodes[1], 0, 560, 
	{
		duration: 2.0,  
		transition: Effect.Transitions.spring
	});
	
	page[which]--;
	
	update_arrows(which);
}

function move_right(which, element)
{
	if(page[which] == total_pages[which]) return;
	
    new Effect.MoveBy($('photos_' + which).childNodes[1], 0, -560, 
	{
		duration: 2.0,  
		transition: Effect.Transitions.spring
	});
	
	page[which]++;
	
	update_arrows(which);
}

function set_total_pages(which, pages)
{
	total_pages[which] = pages;
	page[which] = 1;
}

update_arrows = function(which)
{
	if(page[which] == 1)
	{
		$('arrow_left_' + which).className = 'arrow_left';
	}
	else
	{
		$('arrow_left_' + which).className = 'arrow_left active';
	}
	
	if(page[which] == total_pages[which])
	{
		$('arrow_right_' + which).className = 'arrow_right';
	}
	else
	{
		$('arrow_right_' + which).className = 'arrow_right active';
	}
}