用javascript来实现动画导航效果的代码

.Gnb_btn_div{ 
    width:90px; 
    height:75px; 
    overflow:hidden; 
    display:block; 
    position:absolute; 
}      

.Gnb_btn_img{ 
    width:100%; 
    height:525px; 
    display:block; 
    overflow:hidden; 
    text-indent:-500px; 
} 
#gnb_btn_01 .Gnb_btn_img { 
    background-image:url(http://www.wler.cn/blog/img/friend.gif) 
}

<script type="text/javascript"> 
// <![CDATA[ 
function GNB(_7c){ 
    //初始化一些参数 
    this.iImgNum=7;            //小图片个数 
    this.iImgHeight=75;        //小图片高度 
    this.iOverSpeed=50;        //鼠标经过时候切换的时间 
    this.iOutSpeed=50;        //鼠标离开时候切换的时间 
    this.eventObj=_7c;        //取得图片对象      

    this.MouseOverFlag=false; 
    this.imageIndex=0; 
    if(this.eventObj==null){return;} 
    this.eventObj.parentClass=this;this.eventAssign(); 
}      

GNB.prototype.eventAssign=function(){//注册事件 
    this.eventObj.onmouseover=this.menuMouseOver; 
    this.eventObj.onmouseout=this.menuMouseOut; 
};      

GNB.prototype.menuMouseOver=function(){//鼠标经过 
    if(this.parentClass.MouseOverFlag!=false){return;} 
    this.parentClass.MouseOverFlag=true; 
    this.parentClass.clearTimeOut(); 
    this.parentClass.menuMouseOverTimer(); 
};      

GNB.prototype.menuMouseOut=function(){//鼠标离开 
    this.parentClass.MouseOverFlag=false; 
    this.parentClass.clearTimeOut(); 
    this.parentClass.menuMouseOutTimer(); 
};      

GNB.prototype.menuMouseOverTimer=function(){//经过图片位置递增 
    var _7d=this; 
    if(this.imageIndex>=this.iImgNum){return;} 
    this.eventObj.scrollTop=this.imageIndex*this.iImgHeight; 
    this.imageIndex++; 
    this.setTimerID=setTimeout(function(){_7d.menuMouseOverTimer();},this.iOverSpeed); 
};      

GNB.prototype.menuMouseOutTimer=function(){////经过图片位置递减 
    var _7e=this;if(this.imageIndex<0){return;} 
    this.eventObj.scrollTop=this.imageIndex*this.iImgHeight; 
    this.imageIndex--; 
    this.setTimerID=setTimeout(function(){_7e.menuMouseOutTimer();},this.iOutSpeed); 
};      

GNB.prototype.clearTimeOut=function(){//取消定时 
    clearTimeout(this.setTimerID); 
}; 
// ]]> 
</script>

<div class="Gnb_btn_div" id="gnb_btn_01"> 
<a class="Gnb_btn_img" href="#1" href="#1">找朋友</a> 
</div>      

<script type="text/javascript"> 
// <![CDATA[ 
var GNB1=new GNB(document.getElementById("gnb_btn_01"));//实例单个按钮,当然也可以多个 
// ]]> 
</script>