var navigation = {
    next : function(id, type){
        if (typeof type == 'undefined') type = true;
        if ($(id + ' div div').length > 3){
            var nodes = $(id + ' div div.active');
            if (nodes.length){
                for (var i = 0; i < nodes.length; i++)
                    nodes[i].className = 'item';
                if (type){
                    var node = $(nodes[ nodes.length-1 ]);
                    var limit = 3;
                    if (!node.next().length){
                        node = $(id + ' div div:first').addClass('active');
                        limit = 2;
                    }
                    for (var i = 0; i < limit; i++){
                        if (node.next()){
                            node = node.next();
                            node.addClass('active');
                        }
                    }
                }
                else{
                    var node = $(nodes[0]);
                    var limit = 3;
                    if (!node.prev().length){
                        var list = $(id + ' div div');
                        node = $(list[ list.length-1 ]);
                        node.addClass('active');
                        limit = list.length % 3 - 1;
                    }
                    for (var i = 0; i < limit; i++){
                        if (node.prev()){
                            node = node.prev();
                            node.addClass('active');
                        }
                    }
                }
            }
        }
    },
    prev : function(id){
        navigation.next(id, false);
    }
};