function toggle() {
	
var links = Core.getElementsByClass("toggle_hook");

var prev = document.getElementById("prev");
var next = document.getElementById("next");
var start = document.getElementById("start");

		
	prev.onclick = function() {
	 		if (Core.hasClass(links[12], "port_feat"))
	 			{
					Core.removeClass (links[12], "port_feat")
					Core.addClass (links[11], "port_feat")
					Core.removeClass (next, "hidden")
				}
			else if (Core.hasClass(links[11], "port_feat"))
	 			{
					Core.removeClass (links[11], "port_feat")
					Core.addClass (links[10], "port_feat")
				}
			else if (Core.hasClass(links[10], "port_feat"))
	 			{
					Core.removeClass (links[10], "port_feat")
					Core.addClass (links[9], "port_feat")
				}
			else if (Core.hasClass(links[9], "port_feat"))
	 			{
					Core.removeClass (links[9], "port_feat")
					Core.addClass (links[8], "port_feat")
				}
			else if (Core.hasClass(links[8], "port_feat"))
	 			{
					Core.removeClass (links[8], "port_feat")
					Core.addClass (links[7], "port_feat")
				}
			else if (Core.hasClass(links[7], "port_feat"))
	 			{
					Core.removeClass (links[7], "port_feat")
					Core.addClass (links[6], "port_feat")
				}
			else if (Core.hasClass(links[6], "port_feat"))
	 			{
					Core.removeClass (links[6], "port_feat")
					Core.addClass (links[5], "port_feat")
				}
			else if (Core.hasClass(links[5], "port_feat"))
	 			{
					Core.removeClass (links[5], "port_feat")
					Core.addClass (links[4], "port_feat")
				}
			else if (Core.hasClass(links[4], "port_feat"))
	 			{
					Core.removeClass (links[4], "port_feat")
					Core.addClass (links[3], "port_feat")
				}
			else if (Core.hasClass(links[3], "port_feat"))
	 			{
					Core.removeClass (links[3], "port_feat")
					Core.addClass (links[2], "port_feat")
				}
			else if (Core.hasClass(links[2], "port_feat"))
	 			{
					Core.removeClass (links[2], "port_feat")
					Core.addClass (links[1], "port_feat")
				}
			else if (Core.hasClass(links[1], "port_feat"))
	 			{
					Core.removeClass (links[1], "port_feat")
					Core.addClass (links[0], "port_feat")
					Core.addClass (prev, "hidden")
					Core.addClass (next, "hidden")
					Core.removeClass (start, "hidden")
				}
		return false;
	}
	
	
	next.onclick = function() {
		 if (Core.hasClass(links[1], "port_feat"))
	 			{
					Core.removeClass (links[1], "port_feat")
					Core.addClass (links[2], "port_feat")
				}
		else if (Core.hasClass(links[2], "port_feat"))
	 			{
					Core.removeClass (links[2], "port_feat")
					Core.addClass (links[3], "port_feat")
				}
		else if (Core.hasClass(links[3], "port_feat"))
	 			{
					Core.removeClass (links[3], "port_feat")
					Core.addClass (links[4], "port_feat")
				}
		else if (Core.hasClass(links[4], "port_feat"))
	 			{
					Core.removeClass (links[4], "port_feat")
					Core.addClass (links[5], "port_feat")
				}
		else if (Core.hasClass(links[5], "port_feat"))
	 			{
					Core.removeClass (links[5], "port_feat")
					Core.addClass (links[6], "port_feat")
				}
		else if (Core.hasClass(links[6], "port_feat"))
	 			{
					Core.removeClass (links[6], "port_feat")
					Core.addClass (links[7], "port_feat")
				}
		else if (Core.hasClass(links[7], "port_feat"))
	 			{
					Core.removeClass (links[7], "port_feat")
					Core.addClass (links[8], "port_feat")
				}
		else if (Core.hasClass(links[8], "port_feat"))
	 			{
					Core.removeClass (links[8], "port_feat")
					Core.addClass (links[9], "port_feat")
				}
		else if (Core.hasClass(links[9], "port_feat"))
	 			{
					Core.removeClass (links[9], "port_feat")
					Core.addClass (links[10], "port_feat")
				}
		else if (Core.hasClass(links[10], "port_feat"))
	 			{
					Core.removeClass (links[10], "port_feat")
					Core.addClass (links[11], "port_feat")
				}
		else if (Core.hasClass(links[11], "port_feat"))
	 			{
					Core.removeClass (links[11], "port_feat")
					Core.addClass (links[12], "port_feat")
					Core.addClass (next, "hidden")
				}
		return false;
	}
	
	start.onclick = function() {
		if (Core.hasClass(links[0], "port_feat"))
	 			{
					Core.removeClass (links[0], "port_feat")
					Core.addClass (links[1], "port_feat")
					Core.removeClass (prev, "hidden")
					Core.removeClass (next, "hidden")
					Core.addClass (start, "hidden")
				}
		return false;
	}
	
	links[0].onclick = function() {
			Core.removeClass (start, "hidden")
			Core.addClass (next, "hidden")
			Core.addClass (prev, "hidden")
			return false;
	}
	
	links[1].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[2].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[3].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[4].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[5].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[5].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[6].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[7].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[8].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[9].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[10].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[11].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.removeClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	links[12].onclick = function() {
			Core.removeClass (prev, "hidden")
			Core.addClass (next, "hidden")
			Core.addClass (start, "hidden")
			return false;
	}
	
}

window.onload=toggle;