// JavaScript Document
        function VScrollPanel() {
            this.width = null; //滚动范围宽度
            this.height = null; //滚动范围高度
            this.delay = 100;  //时间延迟
            this.step = 1;  //单步滚动像素
        }
        VScrollPanel.prototype = {
            //滚动指定ID的内容
            Bind: function (domID) {
                this.dom = document.getElementById(domID);
                if (this.width) {
                    this.dom.style.width = this.width + "px";
                }
                if (this.height) {
                    this.dom.style.height = this.height + "px";
                }
                this.dom.style.overflow = "hidden";

                this.Scrolling();
            },
            //滚动方法
            Scrolling: function () {
                //如果内容太少,已经完全可以显示,不需滚动
                if (this.dom.scrollHeight <= this.dom.clientHeight) return;
                
                //滚动到最后一项,切换位置
                if (this.willSwap) {
                    this.dom.appendChild(this.lastOne);
                    this.willSwap = false;
                }
                
                //一个对象自身的引用
                var _this = this;
                
                if (this.dom.scrollTop+ this.step + this.dom.clientHeight
                    >= this.dom.scrollHeight) {
                    //滚动到达底部
                    
                    //删除临时添加的首项
                    if (this.tmp != null) this.dom.removeChild(this.tmp);
                    
                    //复制第一项,即将移至最后一项
                    this.lastOne = this.dom.firstChild;
                    this.tmp = this.lastOne.cloneNode(true);
                    
                    //添加第一项
                    //this.lastOne.replaceNode(this.tmp);
                    //在此用replaceChild替代replaceNode即可兼容FF
                    this.dom.replaceChild(this.tmp,this.lastOne);
                    /*至于为什么要复制第一项，并临时插入
                    是因为如果在滚动内容刚好足够滚动时，如果没有这个临时项，
                    直接移动第一项到最后一项的时候，会发生跳动现象。
                    也就是，比如：如果有4项，不会发生滚动，而如果有5项的时候，就发生这种现象
                    但6项以上的时候，正常*/
                    
                    this.willSwap = true;
                }
                this.dom.scrollTop += this.step;
                setTimeout(function () {
                        /*此处必须用 _this 代替 this 否则错误，原因在此不阐述*/
                        _this.Scrolling();
                    }, this.delay);
            },
            Pause: function () {
                this.pauseStep = this.step;
                this.step = 0;
            },
            Continue: function () {
                this.step = this.pauseStep;
            }
        };

        /*经过多次实验，水平滚动通过新建一个表格来设置布局
        才能最有效的保证布局不会乱，不会发生换行
        所以只好水平、垂直滚动的分开做了*/
        
        //水平滚动。以下代码思路同上，不再注释
        function HScrollPanel() {
            this.width = null;
            this.height = null;
            this.delay = 100;
            this.step = 1;
        }
        HScrollPanel.prototype = {
            Bind: function (domID) {
                this.dom = document.getElementById(domID);
                this.rootDom = document.createElement("table");
                this.rootDom.border = "0";
                this.rootDom.cellPadding = "0";
                this.rootDom.cellSpacing = "0";
                var tbody = document.createElement("tbody");
                this.rootDom.appendChild(tbody);
                this.row = document.createElement("tr");
                tbody.appendChild(this.row);

                var child = this.dom.firstChild;
                while (child != null) {
                    this.dom.removeChild(child);
                    if (child.nodeType == 1) {
                        var td = document.createElement("td");
                        td.vAlign = "top";
                        td.appendChild(child);
                        this.row.appendChild(td);
                    }
                    child = this.dom.firstChild;
                }
                this.dom.appendChild(this.rootDom);


                if (this.width) {
                    this.dom.style.width = this.width + "px";
                }
                if (this.height) {
                    this.dom.style.height = this.height + "px";
                }
                this.dom.style.overflow = "hidden";
                this.Scrolling();
            },
            Scrolling: function () {
                if (this.dom.scrollWidth <= this.dom.clientWidth) return;
                if (this.willSwap) {
                    this.row.appendChild(this.lastOne);
                    this.willSwap = false;
                }
                var _this = this;
                if (this.dom.scrollLeft + this.step + this.dom.clientWidth
                    >= this.dom.scrollWidth) {
                    if (this.tmp != null) {
                        this.row.removeChild(this.tmp);
                    }
                    this.lastOne = this.row.firstChild;
                    this.tmp = this.lastOne.cloneNode(true);
                    //this.lastOne.replaceNode(this.tmp);
                    this.row.replaceChild(this.tmp,this.lastOne);
                    this.willSwap = true;
                }
                this.dom.scrollLeft += this.step;
                setTimeout(function () { _this.Scrolling(); }, this.delay);
            },
            Pause: function () {
                this.pauseStep = this.step;
                this.step = 0;
            },
            Continue: function () {
                this.step = this.pauseStep;
            }
        };