cookie shim with localStorage

gistfile1.txt

    var cookieVal = document.cookie,
        testVal = "mixpanel",
        localStorageKey = "mixpanel-cookie",
        canWriteCookie = false;

    // Test cookie
    document.cookie = testVal;
    canWriteCookies = document.cookie === testVal;

    // Restore cookie
    document.cookie = cookieVal;

    if (!canWriteCookie) {
        Object.defineProperty(
            document,
            "cookie",
            {
                get: function () {
                    return window.localStorage.getItem(localStorageKey);
                },
                set: function (val) {
                    window.localStorage.setItem(localStorageKey, val);
                }
            }
        );
    }