function clearCookie(cookieName) {
	var now = new Date();
	var yesterday = new Date(now.getTime() - 1000 * 60 * 60 * 24);
	document.setCookie(cookieName, '', yesterday);
}
 
function setCookie(cookieName, cookieValue, nDays) {
	var today = new Date();
	var expire = new Date();
	if (nDays == null || nDays == 0) nDays = 1;
	expire.setTime(today.getTime() + 3600000 * 24 * nDays);
	document.cookie = cookieName+"="+escape(cookieValue)+";expires="+expire.toGMTString();
}
 
function getCookie(cookieName) {
	var cookieValue = '';
	var posName = document.cookie.indexOf(escape(cookieName) + '=');
	if (posName != -1) {
		var posValue = posName + (escape(cookieName) + '=').length;
		var endPos = document.cookie.indexOf(';', posValue);
		if (endPos != -1) {
			cookieValue = unescape(document.cookie.substring(posValue, endPos));
		} else {
			cookieValue = unescape(document.cookie.substring(posValue));
		}
	}
	return cookieValue;
}