var screens = 1;
var current = 1;

function nextScreen ()
{
	var id = current + 1;
	if (id <= 15)
	{
		if (id < 10) { id = "0" + id; }
		showScreen(id);
	}
}

function showScreen (id)
{
	var root = document.getElementById("screen_sections");
	var tables = root.getElementsByTagName("table");

	current = parseInt(id, 10);

	for (var i = 0; i < tables.length; i++)
	{
		tables[i].style.display = "none";
	}

	var sec = document.getElementById("screen_section_" + id);
	sec.style.display = "block";

	root = document.getElementById("screen_index");
	var as = root.getElementsByTagName("a");
	for (var i = 0; i < as.length; i++)
	{
		as[i].className = "";
	}
	var a = document.getElementById("screen_index_" + id);
	a.className = "active";

	var el = document.getElementById("screen_id");
	el.innerHTML = id;
}