var slideshow_timer = 0;
var slideshow_timeout = 7000;
var slideshow_frame = 2;
var slideshow_frames = 4;

function slideshow_start(timeout)
{
	slideshow_timer = window.setTimeout(slideshow_tick, timeout);
}

function slideshow_show(tab_number)
{
	for(var i = 0; i < slideshow_frames; i++)
	{
		var scr = $('slideshow_screen' + i);
		var tab = $('slideshow_tab' + i);
		if(tab_number == i)
		{
			tab.src = '/images/home/slideshow/tab' + i + '_up.jpg';
			scr.style.display = "block";
		}
		else
		{
			tab.src = '/images/home/slideshow/tab' + i + '_down.jpg';
			scr.style.display = "none";
		}
	}
}

function slideshow_jump(tab_number)
{
	slideshow_stop();
	slideshow_show(tab_number);
}

function slideshow_tick()
{
	slideshow_frame = (slideshow_frame + 1) % slideshow_frames;
	slideshow_show(slideshow_frame);
	slideshow_start(slideshow_timeout);
}

function slideshow_stop()
{
	if(slideshow_timer)
	{
		window.clearTimeout(slideshow_timer);
		slideshow_timer = null;
	}
}

/* Start the slideshow */
Event.observe(window, 'load', function() { slideshow_start(5000); });