(function($){
$.fn.extend({
        Scroll:function(opt,callback){
                //参数初始化
                if(!opt) var opt={};
                var _btnUp = $("#"+ opt.up);
                var _btnDown = $("#"+ opt.down);
                var timerID;
                var _this=this.eq(0).find("ul:first");				
				var _li_size=$("."+ opt.list_ul+" li").size();
				var _display_li=4;
				var _move_num=_li_size-_display_li;
				var _move_now_num=0;
                var     lineH=_this.find("li:first").height(), 
                        line=opt.line?parseInt(opt.line,10):parseInt(this.height()/lineH,10), 
                        speed=opt.speed?parseInt(opt.speed,10):500; 
                        timer=opt.timer 
                if(line==0) line=1;
                var upHeight=0-line*lineH;
                if (_li_size <= _display_li)
                {
                  _btnDown.css({"filter":"alpha(opacity=30)","opacity":"0.4","cursor":"default" });
                  _btnUp.css({"filter":"alpha(opacity=30)","opacity":"0.4","cursor":"default" });
                }
                //滚动函数
                var scrollUp=function(){
					
					if (_li_size>_display_li)
					{  
						if(_move_now_num<_move_num)
						{
							_btnUp.unbind("click",scrollUp); 
							_this.animate({
									marginTop:upHeight
							},speed,function(){
									for(i=1;i<=line;i++){
											_this.find("li:first").appendTo(_this);
									}
									_this.css({marginTop:0});
									_btnUp.bind("click",scrollUp);
							});
							_move_now_num++;
							_btnDown.css({"filter":"alpha(opacity=100)","opacity":"1","cursor":"pointer" });	
						}
						else
						{
							_btnUp.css({"filter":"alpha(opacity=30)","opacity":"0.4","cursor":"default" });	
						}
					}

                }
                //Shawphy:向下翻页函数
                var scrollDown=function(){
					if (_li_size>_display_li)
					{
						if(_move_now_num>0)
						{  _move_now_num--;
							_btnUp.css({"filter":"alpha(opacity=100)","opacity":"1","cursor":"pointer" });
							_btnDown.unbind("click",scrollDown);
							for(i=1;i<=line;i++){
									_this.find("li:last").show().prependTo(_this);
							}
							_this.css({marginTop:upHeight});
							_this.animate({
									marginTop:0
							},speed,function(){
									_btnDown.bind("click",scrollDown);
							});
						}
						else
						{
							_btnDown.css({"filter":"alpha(opacity=30)","opacity":"0.4","cursor":"default" });							
						
						}
					}
                }
               //Shawphy:自动播放
                var autoPlay = function(){
                        if(timer)timerID = window.setInterval(scrollUp,timer);
                };
                var autoStop = function(){
                        if(timer)window.clearInterval(timerID);
                };
                 //鼠标事件绑定
                //_this.hover(autoStop,autoPlay).mouseout();
                _btnUp.css("cursor","pointer").click( scrollUp );
                _btnDown.css("cursor","pointer").click( scrollDown );

        }      
})
})(jQuery);