a little bit easier to work with cookies in client-side JS

cookie-helper.js

var CookieHelper = {
		read: function(key) {
			return decodeURI(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*" + encodeURI(key).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=\\s*([^;]*).*$)|^.*$"), "$1")) || null;
		},
		exists: function(key) {
			return (new RegExp("(?:^|;\\s*)" + encodeURI(key).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=")).test(document.cookie);
		},
		write: function(key, value, end, path, domain, secure) {
			if (!key || /^(?:expires|max\-age|path|domain|secure)$/i.test(key)) { return false; }
			var expires = "";
			
			if (end) {
				switch (end.constructor) {
					case Number:
						expires = end === Infinity ? "; expires=Fri, 31 Dec 9999 23:59:59 GMT" : "; max-age=" + end;
						break;
					case String:
						expires = "; expires=" + end;
						break;
					case Date:
						expires = "; expires=" + end.toGMTString();
						break;
				}
			}
			
			document.cookie = encodeURI(key) + "=" + encodeURI(value) + expires + (domain ? "; domain=" + domain : "") + (path ? "; path=" + path : "") + (secure ? "; secure" : "");
			return true;
		},
		destroy: function(key, path, domain) {
			if (!key || !this.hasItem(key)) { return false; }
			document.cookie = encodeURI(key) + "=; expires=Thu, 01 Jan 1970 00:00:00 GMT" + (path ? "; path=" + path : "") + (domain ? "; domain=" + domain : "");
			return true;
		}
	};