solve IE7 & IE8 Storage cookie problem

I've been working on a project recently , You need a browser that is compatible with a lower version , Now it is still used xp Systematic IE7 ！！！！ When I heard the news, I was all bad .
One of these functions requires cookie Store and clear , Found in ie8 And then there is no effect . resolvent ：

/** *  Set up cookie * @param {String} key * @param {String} value * @param {Number} expires  The unit is in seconds  * @param {String} path  route  * @param {String} domain  host  * @param {Boolean} secure  Security level  */
function setCookie(key, value, expires, path, domain, secure) {
    
    // key If it is invalid, do nothing 
    if (!key) {
    
        return;
    }
    //  all cookie Of key All lowercase 
    key = key.toLowerCase();
    key = key + '=' + escape(value) + ";";
    expires = expires ? ("expires=" + new Date(new Date().getTime() + expires * 1000).toGMTString()) + ";" : "";
    path = !!path ? "path=" + path + ";" : "path=/;";
    domain = domain ? ("domain=" + domain) + ";" : "";
    secure = secure ? "secure=true;" : "";
    document.cookie = [key, expires, path, domain, secure].join("");
}

// eliminate cookie
function clearCookie(name) {
    
    var e = new Date();
    e.setTime(e.getTime() - 1);
    var b = getCookie(name);
    document.cookie = name + "=" + name + ";path=/; domain=" + window.location.host + "; expires=" + e.toGMTString()
}

True and effective ！！！！！