真有意思

var HttpCookie = function (name, value, expires, path, domain) {
    if (name) this.Name = name;
    if (value) this.Value = value;
    if (expires) this.Expires = expires;
    if (path) this.Path = path;
    if (domain) this.Domain = domain;
};

HttpCookie.prototype =
{
    Name: '', Value: '', Expires: '', Path: '/', Domain: '',
    toCookie: function () {
        var NewCookie = this.Name + '=' + this.Value;
        if (this.Expires) NewCookie += (';expires=' + this.Expires);
        if (this.Path) NewCookie += (';path=' + this.Path);
        if (this.Domain) NewCookie += (';domain=' + this.Domain);
        return NewCookie;
    }
}

var CookieHelper = function () { };

CookieHelper.ConvertToUTCString = function (hourNumber) {
    if (!hourNumber || hourNumber == 0) return null;
    var Timestamp = (new Date().getTime() + (hourNumber * 1000 * 60 * 60));
    return new Date(Timestamp).toUTCString();
};

CookieHelper.Set = function (cookieName, cookieValue, expireHour, path, domain) {
    var HC =
    new HttpCookie
    (
        cookieName,
        escape(cookieValue),
        CookieHelper.ConvertToUTCString(expireHour),
        path,
        domain
    );

    document.cookie = HC.toCookie();
};

CookieHelper.Get = function (cookieName) {
    var regex = new RegExp(("(^| )" + cookieName + "=([^;]*)(;|$)"));
    var Matchs = document.cookie.match(regex);
    if (Matchs) return unescape(Matchs[2]);
    return null;
};

CookieHelper.Delete = function (cookieName, path, domain) {
    if (!CookieHelper.Get(cookieName)) return;

    var HC =
    new HttpCookie
    (
        cookieName,
        null,
        CookieHelper.ConvertToUTCString(-100)
    );

    document.cookie = HC.toCookie();
};