function show_previous(slideshow) {
	slideshow = slideshow.parentNode.parentNode;
	old_value = parseInt(slideshow.getAttribute("value"));
	new_value = old_value-1;
	if (new_value < 1) { new_value = 1; }
	slideshow.children[old_value-1].className = "slide";
	slideshow.children[new_value-1].className = "slide active";
	slideshow.setAttribute("value", new_value);
}
function show_next(slideshow) {
	slideshow = slideshow.parentNode.parentNode;
	old_value = parseInt(slideshow.getAttribute("value"));
	max_value = slideshow.getElementsByClassName("slide").length;
	new_value = old_value+1;
	if (new_value > max_value) { new_value = max_value; }
	slideshow.children[old_value-1].className = "slide";
	slideshow.children[new_value-1].className = "slide active";
	slideshow.setAttribute("value", new_value);
	scroll(0,0);
}