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                        /前端開發(fā)
                        
                            /JavaScript
                        
                        /JS動(dòng)畫效果

漸變動(dòng)畫哪里有問題？

<!DOCTYPE?html>
<html>
<head>
??<meta?charset="utf-8">
??<title>運(yùn)動(dòng)</title>
??<style?type="text/css">
????#box{
??????width:?200px;
??????height:?200px;
??????opacity:?0.2;
??????background:?red;
??????margin:?20px?auto;
????}
??</style>
??<script?type="text/javascript">
??window.onload=function(){
????var?obox?=?document.getElementById('box');
????obox.onmouseover=function(){
??????move(0.1,1);
????}
????obox.onmouseout=function(){
??????move(-0.1,0.2);
????}
??}
??var?timer=null;
??function?move(a,targat){
????clearInterval(timer);
????var?obox?=?document.getElementById('box'),
????????a,
????????targat;
????????var?b=0.2;
????????timer=setInterval(function(){
??????????if(b==targat){
?????????????clearInterval(timer);
??????????}
??????????else{
????????????b=b+a;
????????????obox.style.opacity=b;
??????????}
???????????
????????},30)
??}
??</script>
</head>
<body>
<div?id='box'></div>
</body>
</html>