<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
body,ul{margin: 0;padding: 0;}
ul,li{
list-style: none;
}
li{
background: yellow;
width: 200px;
height: 100px;
border: 10px solid #000;
margin-bottom: 10px;
}
</style>
</head>
<body>
<script type="text/javascript">
window.onload = function(){
var ali = document.getElementsByTagName('li');
for (var i = 0; i < ali.length; i++) {
ali[i].timer = null;
ali[i].onmouseover = function(){
startMove(this,400);
}
ali[i].onmouseout = function(){
startMove(this,200);
}
}
}
function getStyle(obj.attr){
if (obj.currentStyle) {
return obj.currentStyle[attr];
}
else{
return getComputedStyle(obj,false)[attr];
}
}
function startMove(obj,ita){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var pg = parseInt(getStyle(obj,'width'));
var speed = (ita - pg)/10;
speed = speed > 0?Math.ceil(speed):Math.floor(speed);
if (ita == pg) {
clearInterval(obj.timer);
}
else{
obj.style['width'] = pg + speed +'px';
}
},30)
}
</script>
<ul>
<li id="li1"></li>
<li id="li2"></li>
</ul>
</body>
</html>
