<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style style="text/css">
*{
margin:0;
padding:0;
}
#div1{
width:200px;
height: 200px;
background: red;
filter:alpha(opacity:30); /* 兼容IE */
opacity: 0.3;
}
</style>
<script>
window.onload = function(){
var oDiv = document.getElementById('div1');
oDiv.onmouseover = function(){
startMove(100);
}
oDiv.onmouseout = function(){
startMove(30);
}
}
var timer = null;
var alpha = 30;
function startMove(iTarget){
var oDiv = document.getElementById('div1');
clearInterval(timer);//防止定时器叠加
timer = setInterval(function(){
var speed = 0;
if(alpha > iTarget){
speed = -10;
}else{
speed = 10;
}
if(alpha == iTarget){
clearInterval(timer);
}else{
alpha += speed;
oDiv.style.filter = 'alpha(opacity:'+alpha+')';
oDiv.style.opacity = alpha/100;
}
},30)
}
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>
