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