// JavaScript Document

var issue_string = "03_summer_";
var last_article = 9;

var current_url = document.URL.toLowerCase();
var offset = current_url.lastIndexOf(issue_string) + issue_string.length;
var current = parseInt(current_url.substring(offset, offset + 2), 10);
var previous = current - 1;
if(previous >= 1)
	{
	previous = "0" + previous;
	}
else
	{
	previous = "first";
	}
var next = current + 1;
if(next <= last_article)
	{
	next = "0" + next;
	}
else
	{
	next = "last";
	}

function UpdateMenu()
	{
	if(previous == "first")
		{
		document.getElementById ("backbutton").innerHTML = "&nbsp;";
		}
	if(next == "last")
		{
		document.getElementById ("nextbutton").innerHTML = "&nbsp;";
		}
	}
	
function GoForward()
	{
	if(next != "last")
		{
		document.location = current_url.substring(0, offset) + next + ".html";
		}
	}
	
function GoBack()
	{
	if(previous != "first")
		{
		document.location = current_url.substring(0, offset) + previous + ".html";
		}
	}