function createCookie(name, value, days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        var expires = "; expires=" + date.toGMTString();
    } else {
        expires = "";
    }
    document.cookie = name + "=" + value + expires + "; path=/";
}

function readCookie(name) {
    var nameEQ = name + "=",
        ca = document.cookie.split(';'),
        i,
        c,
        len = ca.length;
    for ( i = 0; i < len; i++) {
        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;
}