列表按设定条数定时滚动

/*

• 列表定时滚动效果(javascript)
• @listId :滚动列表ID
• @listTagName :滚动元素
• @scrollNum :设置滚动元素数量
• @speed : 滚动速度
  */

  function fnScrollList() {
    this.init.apply(this, arguments);
  }

  fnScrollList.prototype = {
    init: function (listId, TagName, scrollNum, speed) {
      var _this = this;
      this.oList = this.$$(listId);
      this.scrollTimer = null;
      this.speed = speed || 1000;
      this.scrollNum = scrollNum || 0;
      this.TagName = TagName;
      this.distance = this.oList.getElementsByTagName(TagName)[0].offsetHeight * this.scrollNum;//列表移动距离
      this.oList.style.marginTop = 0 + "px";

      this.oList.onmouseover = function () {
        _this.pause();
      }
      this.oList.onmouseout = function () {
        _this.scrollTimer = setTimeout(function () {
          _this.play();
        }, _this.speed);
      }
      this.play();
    },
    play: function () {
      var _this = this;
      var options = {'marginTop': '-' + _this.distance};
      _this.anim(_this.oList, options, function () { //回调函数，移动列表元素
        for (var i = 0, j = 0; i < _this.scrollNum; i++) {
          var node = _this.oList.getElementsByTagName(_this.TagName)[j];
          if (_this.TagName == "tr") {
            _this.oList.getElementsByTagName('tbody')[0].appendChild(node);
          } else {
            _this.oList.appendChild(node);
          }
        }
        _this.oList.style.marginTop = "0px";
      });

      _this.scrollTimer = setTimeout(function () {
        _this.play(_this.distance);
      }, _this.speed);
    },
    pause: function () {
      clearTimeout(this.scrollTimer);
    },
    //动画函数
    anim: function (oElement, oAttr, fnCallback) {
      var _this = this;
      clearInterval(oElement.timer);
      oElement.timer = setInterval(function () {
        var bStop = true;
        for (var property in oAttr) {
          var iCur = parseFloat(_this.css(oElement, property)); //获取当前位置属性值
          var iSpeed = (oAttr[property] - iCur) / 5; //移动进度
          iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);
          if (iCur != oAttr[property]) { //如果当前数值不等于目标数值，则数值递增
            bStop = false;
            _this.css(oElement, property, iCur + iSpeed);
          }
        }
        if (bStop) {
          clearInterval(oElement.timer);
          fnCallback && fnCallback.apply(_this, arguments);
        }
      }, 50);
    },
    //处理样式函数
    css: function (oElement, attr, value) {
      if (arguments.length == 2) {
        return oElement.currentStyle ? oElement.currentStyle[attr] : getComputedStyle(oElement, null)[attr];
      } else if (arguments.length == 3) {
        switch (attr) {
          case "top":
          case "left":
          case "marginTop":
            oElement.style[attr] = value + "px";
            break;
          default:
            oElement.style[attr] = value;
            break;
        }
      }
    },
    $$: function (o) {
      if (o) {
        return document.getElementById(o);
      }
    }
  };

  var list = new fnScrollList('list', 'li', 0, 3000);