var main=function() {
    $('.article').click(function() {
        $(this).addClass('current');
        $(this).children('.description').show();
    });

    $(document).keypress(function(event) {
        if (event.which === 110) {
          var currentArticle = $('.current');
          var nextArticle = currentArticle.next();

          currentArticle.removeClass('current');
          nextArticle.addClass('current');
        }
    });
};

$(document).ready(main);