                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JS動畫效果

透明度沒有變化，請大神指教

<!DOCTYPE?HTML>
<html>
	<head>
		<meta?http-equiv="Content-Type";content="text/html";charset="utf-8"/>
		<title>透明度的改變</title>
		<style?type="text/css">
			*{
				margin:0;
				padding:0;
			}
			#did{
				width:200px;
				height:200px;
				background:red;
				filter:alpha(opacity:30);
	????????????opacity:0.3;
				margin:auto;
			}
		</style>
		<script?type="text/JavaScript">
			window.load=function(){
				var?oDiv?=?document.getElementById("did");
				oDiv.onmouseover=function(){
					startChange(100);
				}
				oDiv.onmouseout=function(){
					startChange(30);
				}
			}
			var?timer?=?null;
			var?speed?=?0;
			var?alpha?=?30;
			function?startChange(itarget){
				var?oDiv?=?document.getElementById("did");
				clearInterval(timer);
				timer?=?serInterval(function(){
					if(alpha>itarget){
						speed?=?-10;
					}
					else{
						speed?=?10;
					}

					if(alpha?==?itarget){
						clearInterval(timer);
					}
					else{
						alpha?+=?speed;
						oDiv.style.filter?=?'alpha(opacity:'+alpha+')';
						oDiv.style.opacity?=?alpha/100;

					}

				},30)
			}
		</script>
	</head>
	<body>
		<div?id="did"></div>
	</body>
</html>

找了好久的錯誤，都沒有找到，眼已瞎，求大神看看！1