使用运动框架为什么实现不了borderWidth 的变化功能，请高手指点。代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>边框运动</title>
<style>
div{width:100px; height:100px; margin:20px; float:left; background:yellow; border:2px solid green;
filter:alpha(opacity=30);
opacity:0.3;
}
</style>
<script>
function getStyle(obj,name){
if(obj.currentStyle){
return obj.currentStyle[name]}else{
return getComputedStyle(obj,false)[name];
}
}
window.onload=function(){
var aDiv1=document.getElementById('div1');
;
var oTxt=document.getElementById('txt');
aDiv1.onmouseover=function(){
startMove(this,'borderWidth',100);
}
aDiv1.onmouseout=function(){
startMove(this,'borderWidth',30);
}
/*aDiv1.onmouseover=function(){
startMove(this,'width',400);
}
aDiv1.onmouseout=function(){
startMove(this,'width',100);
}*/
}
function startMove(obj,attr,iTarget){
clearInterval(obj.timer);
obj.timer=setInterval(function(){
var cur=parseInt(getStyle(obj,attr))
if(attr=='opacity'){
cur=parseFloat(getStyle(obj,attr))*100;
}else{
cur=parseInt(getStyle(obj,attr));
}
var speed=(iTarget-cur)/4;
speed=speed>0?Math.ceil(speed):Math.floor(speed);
if(cur==iTarget){
clearInterval(obj.timer);}
else{
if(attr=='opacity'){
obj.style.filter='alpha(opacity:'+cur+speed+')';
obj.style.opacity=(cur+speed)/100;
var oTxt=document.getElementById('txt');
oTxt.value= obj.style.opacity;
}else{
obj.style[attr]=cur+speed+'px';
var oTxt=document.getElementById('txt');
oTxt.value= cur+speed;}
}
},30)
}
</script>
</head>
<body>
<input id='txt' type="text" />
<div id='div1'>边框运动</div>
</body>
</html>
