function init() {
	body_class_name = getCookie("bodyClassName");
	setBodyBackground(body_class_name);
}

function background_switcher(body_class_name){
	setBodyBackground(body_class_name);
	setCookie("bodyClassName", body_class_name);
}

function setBodyBackground(class_name) {
	document.body.className = class_name;
}

function setCookie(name, value) {
	document.cookie = name + "=" + value;	
}

function getCookie(name) {
	var pos = document.cookie.indexOf(name + "=");
	if(pos == -1) {
		return "aluminum";
	} else {
		var pos2 = document.cookie.indexOf(";", pos);
		if(pos2 == -1) {
			return unescape(document.cookie.substring(pos + name.length +1));
		} else {
			return unescape(document.cookie.substring(pos + name.length + 1, pos2));
		}
	}
}