Uncaught TypeError: Cannot read property 'currentStyle' of undefined"
<!DOCTYPE html>
<html>
?? ?<head>
?? ??? ?<meta charset="UTF-8">
?? ??? ?<title></title>
?? ??? ?<style>
*{
?? ?margin: 0;
?? ?padding: 0;
}
#div1{
?? ?width:200px;
?? ?height: 100px;
?? ?background: yellow;
?? ?margin-top: 10px;
?? ?border:5px solid black;
?? ?font-size: 12px;
?? ?filter:alpha(opacity=30);
?? ?opacity: 0.3;?? ?
}
?? ??? ?</style>
?? ??? ?<script>
?? ??? ??? ?window.onload = function(){
?? ??? ??? ??? ?var div1=document.getElementById("div1");
?? ??? ??? ??? ?div1.onmouseover=function(){
?? ??? ??? ??? ??? ?move(this,"width",400);
?? ??? ??? ??? ?}
?? ??? ??? ??? ?div1.onmouseout=function(){
?? ??? ??? ??? ??? ?move(this,"width",200);
?? ??? ??? ??? ?}
?? ??? ??? ?}?? ??? ?
?? ??? ??? ?var timer=null;?? ??? ??? ?
?? ??? ??? ?function move(obj,attr,target){
?? ??? ??? ??? ?clearInterval(timer);?? ??? ??? ??? ?
?? ??? ??? ??? ? timer=setInterval(function(){
?? ??? ??? ??? ? ?? ?var icur =0;
?? ??? ??? ??? ? ?? ?if (attr = "opacity") {
?? ??? ??? ??? ? ?? ??? ??? ?icur = Math.round(parseFloat(getstyle(obj.attr))*100);
?? ??? ??? ??? ? ?? ?} else{
?? ??? ??? ??? ? ?? ??? ?var icur = parseInt(getstyle(obj,attr));
?? ??? ??? ??? ? ?? ?}
?? ??? ??? ??? ? ?? ?
?? ??? ??? ??? ??? ?var speed =(target-icur)/8;?? ?
?? ??? ??? ??? ??? ??? ?speed =speed>0?Math.ceil(speed):Math.floor(speed);
?? ??? ??? ??? ??? ?if(target==icur){
?? ??? ??? ??? ??? ??? ?clearInterval(timer);
?? ??? ??? ??? ??? ?}else{
?? ??? ??? ??? ??? ?if (attr = "opacity") {
?? ??? ??? ??? ??? ??? ?obj.style.filter ="alpha(opacity:"+(icur+speed)+")"
?? ??? ??? ??? ??? ??? ??? ?obj.style.opacity = (icur+speed)/100;
?? ??? ??? ??? ??? ??? ?} else{
?? ??? ??? ??? ??? ??? ??? ?obj.style[attr] = icur+speed+"px";?? ??? ?
?? ??? ??? ??? ??? ??? ?}?? ??? ??? ??? ??? ?
?? ??? ??? ??? ??? ?}
?? ??? ??? ??? ?},30)
?? ??? ??? ?}
?? ??? ?function getstyle(obj,attr){?? ??? ??? ?
?? ??? ??? ?if(obj.currentStyle){
?? ??? ??? ??? ?return obj.currentStyle[attr];
?? ??? ??? ?}else{
?? ??? ??? ??? ?return getComputedStyle(obj,false)[attr];
?? ??? ??? ?}
?? ??? ?}
?? ?</script>
?? ?</head>
?? ?<body>
?? ??? ?<div id="div1" >font-size</div>
?? ?</body>
</html>
一直報錯：Uncaught TypeError: Cannot read property 'currentStyle' of undefined"
誰能告訴我為什么?。?！
