Simple cookie management class

JS Cookie Class.js

function Cookie () {
	this.cookieKey = "YOUR-KEY-HERE";
	this.createCookie = function (value, days) {
		if (days) {
			var date = new Date();
			date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
			var expires = "; expires=" + date.toGMTString();
		}
		else {
			var expires = "";
		}
		document.cookie = this.cookieKey + "=" + value + expires + "; path=/";
	};
	this.readCookie = function () {
		var nameEQ = this.cookieKey + "=";
		var ca = document.cookie.split(';');
		for (var i = 0; i < ca.length; i += 1) {
			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;
	};
	this.eraseCookie = function () {
		this.createCookie("", -1);
	};
};

var cookie = new Cookie();