/*scroll*/
var Scroller = Class.create();
Scroller.prototype = {
    initialize:function(options){
        this.commandsWrapId = options.commandsWrapId;
        this.scrollWrapId = options.scrollWrapId;
        this.sectionWidth = options.sectionWidth;
        this.step = options.step;
    },
    scrollTo : function(ev){
        if(!ev)ev = window.event;
        var otriger = getSrcElement(ev);
        while(otriger && otriger.tagName != 'LI'){
            otriger = otriger.parentNode;
        }
        Scroller.runningInstance = otriger.scroller;
        var instance = otriger.scroller;
        for(var i=0;i<instance.triggers.length;i++){
            instance.triggers[i].className = 'command unselected';
        }
        otriger.className = 'command selected';
        
        var index = otriger.scrollIndex;
        if(instance.interval)window.clearInterval(instance.interval);
        instance.targetLeft = index * instance.sectionWidth;
        //计算一个step,要求在500ms内转到指定位置
        instance.step = Math.abs((instance.targetLeft - instance.wrap.scrollLeft)/25);
        instance.interval = window.setInterval(instance.scrollByStep,10);
    },
    scrollByStep : function(){
        var i = Scroller.runningInstance;
        var current = parseInt(i.wrap.scrollLeft);
        if(current > i.targetLeft){
            if(current - i.targetLeft < i.step)i.wrap.scrollLeft = i.targetLeft;
            else i.wrap.scrollLeft = i.wrap.scrollLeft - i.step ;
        }else if(current < i.targetLeft){
            if(i.targetLeft - current < i.step)i.wrap.scrollLeft = i.targetLeft;
            else i.wrap.scrollLeft = i.wrap.scrollLeft + i.step;
        }else{
             if(i.interval){
                window.clearInterval(i.interval);
             }
        }
    },
    bindEvent : function(scroller){
        scroller.wrap = $id(scroller.scrollWrapId);
        var ocommands = $id(scroller.commandsWrapId);
        var olis = $tagsC('LI','command',ocommands);
        scroller.triggers = olis;
        if(olis){
            for(var i=0;i<olis.length;i++){
                olis[i].scrollIndex = i;
                olis[i].scroller = scroller;
                addEvent(olis[i],'mouseover',scroller.scrollTo);
            }
        }
    }
};

需要在页面上调用的css和js代码如下：

Code
<style tpe="text/css">
.scrollCommands{clear:both;width:600px;}
.scrollCommands UL{list-item:none;margin:0px;padding:0px;width:600px;overflow:auto;zoom:1;clear:both}
.scrollCommands UL LI{height:20px;line-height:20px;margin:0px;padding:0px;display:block;float:left;}
.scrollCommands UL LI.command{width:65px;border-top:1px solid #eee;border-left:1px solid #eee;border-right:1px solid #eee;text-align:center}
.scrollCommands UL LI.selected{border-bottom:1px solid #fff;background:#fff;}
.scrollCommands UL LI.unselected{border-bottom:1px solid #f0f0f0;background:#f0f0f0;}
.scrollCommands UL LI.sep{width:10px;border-top:1px solid #fff;border-left:1px solid #fff;border-right:0px solid #fff;border-bottom:1px solid #eee;}
.scrollCommands A{font-size:12px;}
#divScrollWrap{width:600px;overflow:hidden;height:200px;padding:0px;clear:both;margin-bottom:10px;border-bottom:1px solid #eee;border-left:1px solid #eee;border-right:1px solid #eee;}
.scrollSection{width:600px;overflow:hidden;height:200px;background:#fff;float:left}
.scrollSection H3{font-size:14px;display:block;border-bottom:1px solid #f0f0f0;font-weight:normal;margin:0px 0px 5px 0px;padding:2px 2px 2px 10px;}
.scrollSection UL{list-style:none;line-height:20px;padding:0px 0px 0px 6px;margin:0px;}
.scrollSection LI{margin:0px;padding:0px 0px 0px 8px;line-height:20px;background:url(/imgs/punyarrowright.gif) no-repeat left 7px;height:20px;overflow:hidden;}
.w280{width:280px;}
</style>
<script type="text/javascript">
addLoadEvent(function(){
var scroller = new Scroller({commandsWrapId:'divScrollCommands',scrollWrapId:'divScrollWrap',sectionWidth:600,step:10});
scroller.bindEvent(scroller);});
</script>