(function($){
    $.fn.textSlider = function(options){
        //默认配置
        var defaults = {
            speed:40,  //滚动速度,值越大速度越慢
            line:1     //滚动的行数
        };

        var opts = $.extend({}, defaults, options);

        var $timer;
        function marquee(obj, _speed){
            var top = 0;
            var margintop;
            $timer = setInterval(function(){
                top++;
                margintop = 0-top;
                obj.find("ul").animate({
                    marginTop: margintop
                },0,function(){
                    var s = Math.abs(parseInt($(this).css("margin-top")));
                    if(s >=obj.find("li").height()){
                        top = 0;
                        $(this).css("margin-top", 0);   //确保每次都是从0开始，避免抖动
                        $(this).find("li").slice(0, 1).appendTo($(this));
                    }
                });
            }, _speed);
        }

        this.each(function(){
            var speed = opts["speed"],line = opts["line"],_this = $(this);
            var $ul =_this.find("ul");
            if($ul.height() > _this.height()){
                marquee(_this, speed);
            }

            //触摸开始
            _this.on('touchstart', function(ev){
                //ev.preventDefault();
                clearInterval($timer);
            });

            //向上滑动
            _this.on('swipeup', function(ev){
                //ev.preventDefault();
                clearInterval($timer);
                if($ul.height() > _this.height()){
                    for(i=0;i<opts.line;i++){
                        $ul.find("li").first().appendTo($ul);
                    }
                    $ul.css("margin-top",0);
                }
            });

            //向下滑动
            _this.on('swipedown', function(ev){
                //ev.preventDefault();
                clearInterval($timer);
                if($ul.height() > _this.height()){
                    for(i=0;i<opts.line;i++){
                        $ul.find("li").first().before($ul.find("li").last());
                    }
                    $ul.css("margin-top",0);
                }
            });

            //触摸结束
            _this.on('touchend',function(ev){
                //ev.preventDefault();
                if($ul.height() > _this.height()){
                    marquee(_this, speed);
                }
            });
        });
    }
})(Zepto);