var currentId = null;

    Effect.Accordion = function (contentId) {
        var slideDown = 0.5;
        var slideUp = 0.5;

        contentId = $(contentId);

        if (currentId != contentId) {
                if (currentId == null) {
                        new Effect.SlideDown(contentId, {duration: slideDown});
                        } else {
                        new Effect.SlideUp(currentId, {duration: slideUp});
                        new Effect.SlideDown(contentId, {duration: slideDown});
                }
                currentId = contentId; 
        } else {
                new Effect.SlideUp(currentId, {duration: slideUp});
                currentId = null;
        }
    };