currentStyle在浏览器里报错，可是不知道错哪儿。大神求看
<script type="text/javascript">
window.onload=function(){
var Li1=document.getElementById('li1');
var Li2=document.getElementById('li2');
Li1.onmouseover=function(){
startMove(this,'opacity',100);
}
Li1.onmouseout=function(){
startMove(this,'opacity',30);
}
}
function getStyle(obj, attr){
if(obj.currentStyle){
return obj.currentStyle[attr];
}
else{return getComputedStyle(obj,false)[attr];
}
}
// var timer=null;
var alpha=30;
function startMove(obj,attr,iTarget){
clearInterval(obj.timer);
obj.timer=setInterval(function(){
var icur=0;
if(attr=='opacity'){
icur=Math.round(parseFloat(getStyle(obj.attr))*100);
}
else{
icur=parseInt(getStyle(obj,attr));
}
var speed=(iTarget-icur)/8;
speed=speed>0?Math.ceil(speed):Math.floor(speed);
if(icur==iTarget){
clearInterval(obj.timer);
}
else{
if(attr=='opacity'){
obj.style.filter='alpha(opacity:'+(icur+speed)+')';
obj.style.opacity=(icur+speed)/100;
}else{
obj.style[attr]=icur+speed+'px';
}
}
},30)
}
</script>
