function Carousel(){
  this.now = 0;          //当前显示的图片索引
  this.hasStarted = false；     //是否开始轮播
  this.interval = null；      //定时器
  this.liItems = null；       //要轮播的li元素集合
  this.len = 0;         //liItems的长度
  this.aBox : null;        //包含指示器的dom对象
  this.bBox : null;        //包含前后按钮的dom对象
  /**
   * 初始化及控制函数
   * @param bannnerBox string 包含整个轮播图盒子的id或class
   * @param aBox string 包含指示器的盒子的id或class
   * @param btnBox string 包含前后按钮的盒子的id或class
   */
  this.startPlay = function(bannnerBox,aBox,btnBox) {
    //初始化对象参数
    var that = this;
    this.liItems = $(bannnerBox).find('ul').find('li');
    this.len = this.liItems.length;
    this.aBox = $(bannnerBox).find(aBox);
    this.bBox = $(bannnerBox).find(btnBox);
    //让第一张图片显示，根据轮播图数量动态创建指示器，并让第一个指示器处于激活状态，隐藏前后按钮
    this.liItems.first('li').css({'opacity': 1, 'z-index': 1}).siblings('li').css({'opacity': 0, 'z-index': 0});
    var aDom = '';
    for (var i = 0; i < this.len; i++){
      aDom += '<a></a>';
    }
    $(aDom).appendTo(this.aBox);
    this.aBox.find('a:first').addClass("indicator-active");
    this.bBox.hide();
    //鼠标移入banner图时，停止轮播并显示前后按钮，移出时开始轮播并隐藏前后按钮
    $(bannnerBox).hover(function (){
      that.stop();
      that.bBox.fadeIn(200);
    }, function (){
      that.start();
      that.bBox.fadeOut(200);
    });
    //鼠标移入指示器时，显示对应图片，移出时继续播放
    this.aBox.find('a').hover(function (){
      that.stop();
      var out = that.aBox.find('a').filter('.indicator-active').index();
      that.now = $(this).index();
      if(out!=that.now) {
        that.play(out, that.now)
      }
    }, function (){
      that.start();
    });
    //点击左右按钮时显示上一张或下一张
    $(btnBox).find('a:first').click(function(){that.next()});
    $(btnBox).find('a:last').click(function(){that.prev()});
    //开始轮播
    this.start()
  };
  //前一张函数
  this.prev = function (){
    var out = this.now;
    this.now = (--this.now + this.len) % this.len;
    this.play(out, this.now);
  };
  //后一张函数
  this.next = function (){
    var out = this.now;
    this.now = ++this.now % this.len;
    this.play(out, this.now);
  };
  /**
   * 播放函数
   * @param out number 要消失的图片的索引值
   * @param now number 接下来要轮播的图的索引值
   */
  this.play = function (out, now){
    this.liItems.eq(out).stop().animate({opacity:0,'z-index':0},500).end().eq(now).stop().animate({opacity:1,'z-index':1},500);
    this.aBox.find('a').removeClass('imgnum-active').eq(now).addClass('indicator-active');
  };
  //开始函数
  this.start = function(){
    if(!this.hasStarted) {
      this.hasStarted = true;
      var that = this;
      this.interval = setInterval(function(){
        that.next();
      },2000);
    }
  };
  //停止函数
  this.stop = function (){
    clearInterval(this.interval);
    this.hasStarted = false;
  }
};

var banner1 = new Carousel();
  var banner2 = new Carousel();
  var banner3 = new carousel();
  banner1.startPlay('#J_bg_ban1','#J_bg_indicator1','#J_bg_btn1');
  banner2.startPlay('#J_bg_ban2','#J_sm_indicator2','#J_bg_btn2');
  banner3.startPlay('#J_bg_ban3','#J_sm_indicator3','#J_bg_btn3');

function Carousel(){
  this.now = 0;          //当前显示的图片索引
  this.hasStarted= false;     //是否开始轮播
  this.interval = null;      //定时器
  this.liItems = null;       //要轮播的li元素集合
  this.len = 0;          //liItems的长度
  this.aBox = null;        //包含指示器的dom对象
  this.bBox = null;        //包含前后按钮的dom对象
  /**
   * 初始化及控制函数
   * @param bannnerBox string 包含整个轮播图盒子的id或class
   * @param aBox string 包含指示器的盒子的id或class
   * @param btnBox string 包含前后按钮的盒子的id或class
   */
  this.startPlay = function(bannnerBox,aBox,btnBox) {
    //初始化对象参数
    var that = this;
    this.liItems = $(bannnerBox).find('ul').find('li');
    this.len = this.liItems.length;
    this.aBox = $(bannnerBox).find(aBox);
    this.bBox = $(bannnerBox).find(btnBox);
    //让第一张图片显示，根据轮播图数量动态创建指示器，并让第一个指示器处于激活状态，隐藏前后按钮
    this.liItems.first('li').css({'opacity': 1, 'z-index': 1}).siblings('li').css({'opacity': 0, 'z-index': 0});
    var aDom = '';
    for (var i = 0; i < this.len; i++){
      aDom += '<a></a>';
    }
    $(aDom).appendTo(this.aBox);
    this.aBox.find('a:first').addClass("imgnum-active");
    this.bBox.hide();
    //鼠标移入banner图时，停止轮播并显示前后按钮，移出时开始轮播并隐藏前后按钮
    $(bannnerBox).hover(function (){
      that.stop();
      that.bBox.fadeIn(200);
    }, function (){
      that.start();
      that.bBox.fadeOut(200);
    });
    //鼠标移入指示器时，显示对应图片，移出时继续播放
    this.aBox.find('a').hover(function (){
      that.stop();
      var out = that.aBox.find('a').filter('.indicator-active').index();
      that.now = $(this).index();
      if(out!=that.now) {
        that.play(out,that.now)
      }
    }, function (){
      that.start();
    });
    //点击左右按钮时显示上一张或下一张
    $(btnBox).find('a:first').click(function(){that.next()});
    $(btnBox).find('a:last').click(function(){that.prev()});
    //开始轮播
    this.start()
  };
  /**
   * 播放函数
   * @param out number 要消失的图片的索引值
   * @param now number 接下来要轮播的图的索引值
   */
  this.play = function (out,now){
    this.liItems.eq(out).stop().animate({opacity:0,'z-index':0},500).end().eq(now).stop().animate({opacity:1,'z-index':1},500);
    this.aBox.find('a').removeClass('imgnum-active').eq(now).addClass('indicator-active');
  };
}
Carousel.prototype = {
  //前一张函数
  prev : function (){
    var out = this.now;
    this.now = (--this.now + this.len) % this.len;
    this.play(out,this.now)
  },
  //后一张函数
  next : function (){
    var out = this.now;
    this.now = ++this.now % this.len;
    this.play(out,this.now);
  },
  //开始函数
  start : function(){
    if(!this.hasStarted) {
      this.hasStarted = true;
      var that = this;
      this.interval = setInterval(function(){
        that.next();
      },2000);
    }
  },
  //停止函数
  stop : function (){
    clearInterval(this.interval);
    this.hasStarted = false;
  }
};