obj is defind 老是报错！？
<!DOCTYPE html>
<html>
<head>
<title>多物体运动</title>
<meta charset="utf-8"/>
<style type="text/css">
ul,li{list-style: none;}
ul li{width: 200px;height: 100px;background-color: yellow;margin-bottom: 20px;border: 4px solid #000;filter:alpha(opaciy:30);opacity: 0.3 }
</style>
<script type="text/javascript">
window.onload = function () {
var li1=document.getElementById("li1");
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=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);// 缓冲运动
if(icur==iTarget) {
clearInterval(obj.timer);
}
else{
if (attr=="opacity") {
obj.style.filter="alpha(opacity:"+(icur+speed)+")";// 针对IE浏览器
obj.style.opacity=(icur+speed)/100;//针对火狐等其他主流浏览器
} else{
obj.style[attr]=icur+speed+"px";// 不加中括号不能运行
}
}
},30);
}
</script>
</head>
<body>
<ul>
<li id="li1"></li>
</ul>
</body>
</html>
