为什么在IE浏览中透明度没有变化，其他浏览器都可以？

var li2=document.getElementById('li1');

var li3=document.getElementById('li2');

li2.timer1=null;

li3.timer1=null;

li2.alpha=100;

li2.onmouseover=function() {

//onMoveMore(this,'width',400);

onMoveMore(this,'opacity',30)

}

li3.onmouseover=function() {

onMoveMore(this,'height',400);

}

li2.onmouseout=function() {

//onMoveMore(this,'width',200);

onMoveMore(this,'opacity',100);

}

li3.onmouseout=function() {

onMoveMore(this,'height',100);

}

function onMoveMore(obj,attr,iTarget){

clearInterval(obj.timer1);

obj.timer1=setInterval(function(){

var icur=0;

if(attr=='opacity'){

icur=Math.round(parseFloat(getStyle(obj,attr))*100);

//alert(icur)

}else{

icur=parseInt(getStyle(obj,attr));

}

speed=(iTarget-icur)/8;

speed=speed>0?Math.ceil(speed):Math.floor(speed);

if(icur==iTarget){

clearInterval(obj.timer1);

}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)

}