current_promo_pos = 0;
promo_count = 0;
promo_scroll_direction = "right";
promo_display_at_once = 4;

function automate_scrolling()
{
	if(promo_count == 0)
		set_promo_count();

	set_direction();
	scroll_promo(promo_scroll_direction);
}
function set_promo_count()
{
	var promos = document.getElementById('promos');
	for(var i=0; i<promos.childNodes.length; i++)
	{
		if(promos.childNodes[i].nodeType == 1)
			promo_count++;
	}

	promo_count--;
}
function set_direction()
{
	if(promo_scroll_direction == "right" && current_promo_pos + promo_display_at_once == promo_count)
		promo_scroll_direction = "left";
	else if(promo_scroll_direction == "left" && current_promo_pos == 0)
		promo_scroll_direction = "right";
}
function scroll_promo(direction)
{
	if(promo_count == 0)
		set_promo_count();

	if(direction == "right" && current_promo_pos + promo_display_at_once == promo_count)
		return;
	else if(direction == "left" && current_promo_pos == 0)
		return;
	
	promo_scroll_direction = direction;
	var promos = document.getElementById('promos');
	if(direction == "right")
	{
		var faster = 33; // 32 pixels * 1 per step
		while(faster--)
			setTimeout('document.getElementById("promos").scrollLeft += 1', .85 * faster * faster);
		
		var slower = 25; // 100 pixels * 4 per step
		while(slower--)
			setTimeout('document.getElementById("promos").scrollLeft += 4', 35 * slower);

		current_promo_pos++;
	}
	else
	{
		var faster = 33; // 34 pixels * 1 per step
		while(faster--)
			setTimeout('document.getElementById("promos").scrollLeft -= 1', .75 * faster * faster);
		
		var slower = 25; // 100 pixels * 4 per step
		while(slower--)
			setTimeout('document.getElementById("promos").scrollLeft -= 4', 30 * slower);

		current_promo_pos--;
	}
}