为什么我的代码不用Math.round()也可以
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>任意属性值</title>
<style type="text/css">
*{margin:0;padding:0;}
body,div {margin:0;padding:0;}
div {
width:200px;
height:200px;
background:red;
margin:10px;
float:left;
filter:alpha(opacity:30);
opacity:0.3;
}
</style>
<script type="text/javascript">
window.onload=function(){
var oDiv=document.getElementById('div1');
oDiv.onmouseover=function(){
startMove(this,'opacity',100);
}
oDiv.onmouseout=function(){
startMove(this,'opacity',30);
}
}
function getStyle(obj,attr){
if(obj.currentStyle){
return obj.currentStyle[attr];
}
else{
return getComputedStyle(obj,false)[attr];
}
}
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);
if(icur==iTarget){
clearInterval(obj.timer);
}
else{
if(attr=='opacity'){//如果传的是透明度
obj.style.filter='alpha(opacity:'+(icur+speed)+')';//针对IE浏览器
obj.style.opacity=(icur+speed)/100;
//针对Firefox
}
else{
obj.style[attr]=icur+speed+'px';
}
}
},30);
}
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>
