请高手帮忙看哈，一下面这段代码的意思。

[wsang_web]

<script type="text/javascript">
var $ = function (id) {
return "string" == typeof id ? document.getElementById(id) : id;
};

var Class = {
create: function() {
return function() {
this.initialize.apply(this, arguments);
}
}
}

Object.extend = function(destination, source) {
for (var property in source) {
destination[property] = source[property];
}
return destination;
}

var TransformView = Class.create();
TransformView.prototype = {
//容器对象,滑动对象,切换参数,切换数量
initialize: function(container, slider, parameter, count, options) {
if(parameter <= 0 || count <= 0) return;
var oContainer = $(container), oSlider = $(slider), oThis = this;

this.Index = 0;//当前索引

this._timer = null;//定时器
this._slider = oSlider;//滑动对象
this._parameter = parameter;//切换参数
this._count = count || 0;//切换数量
this._target = 0;//目标参数

this.SetOptions(options);

this.Up = !!this.options.Up;
this.Step = Math.abs(this.options.Step);
this.Time = Math.abs(this.options.Time);
this.Auto = !!this.options.Auto;
this.Pause = Math.abs(this.options.Pause);
this.onStart = this.options.onStart;
this.onFinish = this.options.onFinish;

oContainer.style.overflow = "hidden";
oContainer.style.position = "relative";

oSlider.style.position = "absolute";
oSlider.style.top = oSlider.style.left = 0;
},
//设置默认属性
SetOptions: function(options) {
this.options = {//默认值
Up: true,//是否向上(否则向左)
Step: 5,//滑动变化率
Time: 10,//滑动延时
Auto: true,//是否自动转换
Pause: 2000,//停顿时间(Auto为true时有效)
onStart: function(){},//开始转换时执行
onFinish: function(){}//完成转换时执行
};
Object.extend(this.options, options || {});
},
//开始切换设置
Start: function() {
if(this.Index < 0){
this.Index = this._count - 1;
} else if (this.Index >= this._count){ this.Index = 0; }

this._target = -1 * this._parameter * this.Index;
this.onStart();
this.Move();
},
//移动
Move: function() {
clearTimeout(this._timer);
var oThis = this, style = this.Up ? "top" : "left", iNow = parseInt(this._slider.style[style]) || 0, iStep = this.GetStep(this._target, iNow);

if (iStep != 0) {
this._slider.style[style] = (iNow + iStep) + "px";
this._timer = setTimeout(function(){ oThis.Move(); }, this.Time);
} else {
this._slider.style[style] = this._target + "px";
this.onFinish();
if (this.Auto) { this._timer = setTimeout(function(){ oThis.Index++; oThis.Start(); }, this.Pause); }
}
},
//获取步长
GetStep: function(iTarget, iNow) {
var iStep = (iTarget - iNow) / this.Step;
if (iStep == 0) return 0;
if (Math.abs(iStep) < 1) return (iStep > 0 ? 1 : -1);
return iStep;
},
//停止
Stop: function(iTarget, iNow) {
clearTimeout(this._timer);
this._slider.style[this.Up ? "top" : "left"] = this._target + "px";
}
};

window.onload=function(){
function Each(list, fun){
for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); }
};

var objs = $("idNum").getElementsByTagName("li");

var tv = new TransformView("idTransformView", "idSlider", 180, 5, {
onStart : function(){ Each(objs, function(o, i){ o.className = tv.Index == i ? "on" : ""; }) }//按钮样式
});

tv.Start();

Each(objs, function(o, i){
o.onmouseover = function(){
o.className = "on";
tv.Auto = false;
tv.Index = i;
tv.Start();
}
o.onmouseout = function(){
o.className = "";
tv.Auto = true;
tv.Start();
}
})


////////////////////////test2


}

</script>

[rainsilence]

断章取义的代码。。 相当于document.getElementById()

var $ = function (id) {
return "string" == typeof id ? document.getElementById(id) : id;
};

javascript没有提供class的定义方法。下面第一个函数定义了Class函数。经过Object.create调用后的function在new的时候会自动调用initialize方法。而第二个函数是属性赋值

var Class = {
  create: function() {
     return function() {
        this.initialize.apply(this, arguments);
     }
  }
}

Object.extend = function(destination, source) {
    for (var property in source) {
         destination[property] = source[property];
    }
    return destination;
}

剩下的代码是TransformView 类，用来实现滚动。原理大概是一个mask层，很小，里面有个放图片啊，什么的div层。然后控制外面的div的scroll让其滑动。scroll bar很有可能是不可见的。 以上代码属于很简单的面向对象封装。如果要完全封装，可以参考我的blog. http://rainsilence.iteye.com/blog/1026530 滑动的原理在这篇： http://rainsilence.iteye.com/blog/891774

[wsang_web]

谢谢，指教。