两种运动同事进行怎么实现?
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>多物体运动</title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
ul,li{
list-style: none;
}
ul li{
width: 200px;
height: 100px;
background: red;
margin-bottom: 20px;
filter:alpha(opacity:30);
opacity: 0.3;
}
</style>
<script>
window.onload = function(){
var aLi = document.getElementsByTagName('li');
for(var i = 0;i < aLi.length;i++){
aLi[i].timer = null;
aLi[i].alpha = 30;
aLi[i].onmouseover = function(){
startMove(this,400);
changeColor(this,100);
}
aLi[i].onmouseout = function(){
startMove(this,200);
changeColor(this,30);
}
}
}
function startMove(obj,iTarget){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var speed = (iTarget-obj.offsetWidth)/10;
speed = speed>0?Math.ceil(speed):Math.floor(speed);
if(iTarget == obj.offsetWidth){
clearInterval(obj.timer);
}
else{
obj.style.width = obj.offsetWidth+speed+'px';
}
},30)
}
function changeColor(obj,iTarget){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var speed = (iTarget - obj.alpha)/10;
speed = speed>0?Math.ceil(speed):Math.floor(speed);
if (iTarget == obj.alpha) {
clearInterval(obj.timer);
}
else{
obj.alpha+=speed;
obj.style.filter = 'alpha(opacity:'+obj.alpha+')';
obj.style.opacity = obj.alpha/100;
}
},30)
}
</script>
</head>
<body>
<ul>
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>如果要实现offseWidth和opacity同时变化要怎样实现?上述方法为什么不能实现?请大神指教