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;
}
function addEventHandler(oTarget, sEventType, fnHandler){
if (oTarget.addEventListener){
oTarget.addEventListener(sEventType, fnHandler, false);
} else if (oTarget.attachEvent){
oTarget.attachEvent("on" + sEventType, fnHandler);
} else{
oTarget["on" + sEventType]=fnHandler;
}
};
var Scroller=Class.create();
Scroller.prototype={
initialize: function(idScroller, idScrollMid, options){
var oScroll=this, oScroller=document.getElementById(idScroller), oScrollMid=document.getElementById(idScrollMid);
this.SetOptions(options);
this.Scroller=oScroller;
this.Speed=this.options.Speed;
this.timer=null;
this.Pause=0;
//用于上下滚动
this.heightScroller=parseInt(oScroller.style.height) || oScroller.offsetHeight;
this.heightList=oScrollMid.offsetHeight;
//js取不到css设置的height和width
oScroller.style.overflow="hidden";
oScrollMid.appendChild(oScrollMid.cloneNode(true));
//方向设置
switch (this.options.Side.toLowerCase()){
case "right" :
if(this.widthList <= this.widthScroller) return;
this.Scroll=this.ScrollLeftRight;
this.side=-1;
break;
case "left" :
if(this.widthList <= this.widthScroller) return;
this.Scroll=this.ScrollLeftRight;
this.side=1;
break;
case "down" :
if(this.heightList <= this.heightScroller) return;
this.Scroll=this.ScrollUpDown;
this.side=-1;
break;
case "up" :
default :
if(this.heightList <= this.heightScroller) return;
this.Scroll=this.ScrollUpDown;
this.side=1;
}
addEventHandler(oScroller, "mouseover", function(){oScroll.Stop();});
addEventHandler(oScroller, "mouseout", function(){oScroll.Start();});
this.Start();
},
//设置默认属性
SetOptions: function(options){
this.options={//默认值
Step:            1,//每次变化的px量
Speed:        20,//速度(越大越慢)
Side:            "up",//滚动方向:"up"是上，"down"是下，"left"是左，"right"是右
PauseHeight:    0,//隔多高停一次
PauseWidth:    0,//隔多宽停一次
PauseStep:    1000//停顿时间(PauseHeight或PauseWidth大于0该参数才有效)
};
Object.extend(this.options, options ||{});
}, 
//上下滚动
ScrollUpDown: function(){
this.Scroller.scrollTop=this.GetScroll(this.Scroller.scrollTop, this.heightScroller, this.heightList, this.options.PauseHeight);
var oScroll=this;
this.timer=window.setTimeout(function(){oScroll.Scroll();}, this.Speed);
},
//获取设置滚动数据
GetScroll: function(iScroll, iScroller, iList, iPause){
var oScroll=this, iStep=this.options.Step * this.side;
if(this.side > 0){
if(iScroll >= (iList * 2 - iScroller)){iScroll -= iList;}
} else{
if(iScroll <= 0){iScroll += iList;}
}
this.Speed=this.options.Speed;
if(iPause > 0){
if(Math.abs(this.Pause) >= iPause){
this.Speed=this.options.PauseStep; this.Pause=iStep=0;
} else{
this.Pause += iStep;
}
}
return (iScroll + iStep);
},
//开始
Start: function(){
this.Scroll();
},
//停止
Stop: function(){
clearTimeout(this.timer);
}
};

window.onload=function(){
new Scroller("Scroller", "ScrollMid",{Step:1, Speed:20, Side:"up", PauseHeight:50, PauseWidth:200, PauseStep:1000});
}