function createCookie(name,value) {
		var date = new Date();
		date.setTime(date.getTime()+(1*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function selectImage() {
	if(!document.getElementById || !document.createTextNode) {
	return
	}
	var images = new Array("image", "clock", "vienna", "greenwich");
	var AltArray = new Array("Greek boats from above, 2006", "Clock, 2005", "S-bahn stop, Vienna, 2006", "Greenwich foot tunnel, London, 2005");
	var selectRandom = Math.floor(Math.random()*(images.length));
	var selectedImageId = images[selectRandom];
	var cookieValue = readCookie("persistentImage");
	if (((cookieValue >=0) & (cookieValue < images.length)) & (cookieValue == parseInt(cookieValue, 10))) {
			selectedImageId = images[cookieValue];
	}
	var selectBody = document.getElementsByTagName("body").item(0);
	selectBody.style.backgroundImage = "url('/graphics/content-" + selectedImageId + ".jpg')";
	selectBody.id = selectedImageId;
}

function graphicNav() {
	if(!document.getElementById || !document.createTextNode) {
		return
	}
	
	var navitems = new Array("music", "web", "edit", "blog", "about", "home");
	var bgColour = "white";
	for (var i=0; i<navitems.length; i++) {
		var itemId = navitems[i];
		var thisNavItem = document.getElementById("nav_"+itemId);
		var thisNavImage = "/graphics/navs/left-navs-"+bgColour+"_"+itemId+".gif";
		var thisNavAlt = thisNavItem.innerHTML;
		
		thisNavItem.innerHTML = "";
		navImage = document.createElement('img');
		navImage.src = thisNavImage;
		navImage.alt = thisNavAlt;
		navImage.border = "0";
		navImage.width = "164";
		thisNavItem.appendChild(navImage);
	}
}

function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
   	window.onload = func;
	} else {
   	window.onload = function() {
   	  	oldonload();
   		func();
   		}
	}
}
addLoadEvent(graphicNav);
addLoadEvent(selectImage);