为什么我的透明度不是变100，而是更加淡了
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>多物体运动</title>
<style type="text/css">
*{margin:0;padding:0;}
ul{
list-style: none;
}
ul li{
width: 200px;
height: 100px;
background: yellow;
margin-bottom: 20px;
border: 5px solid #011;
filter:alpha(opacity:30);
opacity: 0.3;
}
</style>
<script type="text/javascript">
window.onload=function(){
var aLi=document.getElementById('lia');
var bLi=document.getElementById('lib');
aLi.onmouseover=function(){
startMove(this,'opacity',100);
}
aLi.onmouseout=function(){
startMove(this,'opacity',30);
}
function getStyle(obj,attr){
if(obj.currentStyle){
return obj.currentStyle[attr];//针对IE浏览器
}
else{
return getComputedStyle(obj,false)[attr];//针对火狐浏览器
}
}
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 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>
</head>
<body>
<ul>
<li id="lia"></li>
</ul>
</body>
</html>
