                        课程
                    
                        /前端开发
                        
                            /JavaScript
                        
                        /JS动画效果

我按照老师的视频敲的代码怎么实现不了透明度渐变，哪位大神帮忙看下，谢谢！

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>自定义运动框架02</title>
        <style type="text/css">
            *{margin: 0;padding: 0;}
            #div1{
                width: 200px;
                height: 200px;
                background: red;
                background: red;
                filter: alpha(opacity:30);
                opacity: 0.3;
            }
            
            
        </style>
        
        <script type="text/javascript">
            window.onload+function(){
                var odiv=document.getElementById("div1");
                odiv.onmouseover=function(){
                    starMove(100);
                };
                odiv.onmouseout=function(){
                    starMove(30);
                };
            };
            
            var timer=null;
            var alpha=30;
            function starMove(morm){
                var odiv=document.getElementById("div1");
                clearInterval(timer);
                timer=setInterval(function(){
                    var speed=0;
                    if (speed>morm) {
                        speed=-10;
                    } else{
                        speed=10;
                    };
                    if(alpha==morm){
                        clearInterval(timer);
                    }else{
                        alpha+=speed;
                        odiv.style.filter="alpha(opactiy:"+alpha+")";
                        odiv.style.opacity=alpha/100;
                    };
                },30);
            };
            
        </script>
        
    </head>
    <body>
        <div id="div1"></div>
    </body>
</html>