function setBG(level) {
	var setCookies = document.cookie;
	if (setCookies == "") {
		changeBG('purple', level);
	} else {
		var startPoint = setCookies.indexOf("BGcolour=");
		var newStartPoint = startPoint + 9;
		var endPoint = setCookies.indexOf(";", newStartPoint);
		if (endPoint == -1) {
			endPoint = setCookies.length;
		}
		var cookieSplit = setCookies.substring(newStartPoint, endPoint);
		changeBG(cookieSplit, level);
	}
}
function changeBG(backColour, level) {
	var bgImg;
	if (backColour == "purple") {
		bgImg = "purple.css";
	} else if (backColour == "blue") {
		bgImg = "blue.css";
	} else {
		bgImg = "green.css";
	}
	if (level == 1) {
		bgImg = "../" + bgImg;
	}
	document.getElementById('BackgroundStyle').href=bgImg;
	document.cookie='BGcolour='+escape(backColour);
}