<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
body,div{
margin: 0;
padding: 0;
}
#div1{
width: 200px;
height: 200px;
background: red;
filter:alpha(opacity:30);
opacity: 0.3;
}
</style>
</head>
<body>
<div id="div1"></div>
<script>
window.onload=function () {
var odiv=document.getElementById('div1')
odiv.onmouseover=function () {startMove(100);}
odiv.onmouseout=function () {startMove(30);}
}
var times=null;
var alpha=30;
var speed=0;
function startMove(iTarget) {
clearInterval(times);
times=setInterval(function(){
var odiv=document.getElementById('div1');
if(alpha>iTarget){
speed=-10;
}
else{
speed=10;
}
if(alpha==iTarget){
clearInterval(times);
}
else{
alpha+=speed;
odiv.style.filter='alpha(opacity:'+alpha+')';
odiv.stlye.opacity=alpha/100;
}
},30)
}
</script>
</body>
</html>
