/*** js ***/
mw.loader.using(['jquery.cookie'], function () {
    $('.ajax-poll').each(function () {
        var $poll = $(this),
            pollId = $poll.attr('id').split('-')[2],
            cookieName = 'mainpage-poll',
            cookie = $.cookie(cookieName);

        console.log(pollId);

        if (cookie === pollId) {
            $poll.addClass('voted')
        } else {
            // setting value to null removes it
            $.cookie(cookieName, null);
        }

        $poll.find('input[type="submit"]').on('click', function () {
            $poll.addClass('voted');
            $.cookie(cookieName, pollId, { path: '/', expires: 365 });
        });
    });
});

/*** css ***/
.ajax-poll .pollAnswerVotes {
    display: none;
}

.ajax-poll.voted .pollAnswerVotes {
    display: block;
}