// JavaScript Document<script type="text/javascript" language="javascript">

var CloseImage = document.createElement("img");
var EloseImage = document.createElement("img");
var collapsePic='images/3.jpg';
var expandPic='images/2.jpg';
var timer = 5;        //计时器时钟
var HeightEnd=510;//Div高度
var aNum = 10;        //步进速度
var isOpen = false;//层状态 打开还是关闭 默认关闭
//function $(name){return document.getElementById(name);}
function voids() {
    setTimeout("extend()",100);
}


//    展开/关闭
function extend(){
    var tHeight = parseInt(gs(document.getElementById("box"),"height"));
    if(!isOpen){
        document.getElementById("box").style.display="block";
        if (tHeight<HeightEnd){
            document.getElementById("box").style.height=(tHeight+aNum)+"px";
            document.getElementById("box").filters.alpha.opacity+=3;
            setTimeout("extend()",timer);
        }else{
            isOpen=true;    //打开状态
			//CloseImage('src', collapsePic);
          //  document.getElementById("tabTop").innerHTML = "collapsePic";
            document.getElementById("box").filters.alpha.opacity=100;
        }
    }else{
        if((tHeight-aNum)>0){
            document.getElementById("box").style.height=(tHeight-aNum)+"px";
            document.getElementById("box").filters.alpha.opacity-=3;
            setTimeout("extend()",timer);
        }else{
            isOpen=false;    //关闭状态
            document.getElementById("box").style.display="none";
			//EloseImage('src', expandPic);
           // document.getElementById("tabTop").innerHTML = "expandPic";
            document.getElementById("box").filters.alpha.opacity=100;
        }
    }
}

function gs(d,a){
if (d.currentStyle){ 
    var curVal=d.currentStyle[a]
}else{ 
    var curVal=document.defaultView.getComputedStyle(d, null)[a]
} 
return curVal;
}