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                        /JavaScript進階篇

求大神幫我看看代碼沒有效果, 哪里出問題了,找了半天!多謝了

<!doctype?html>
<html>
	<head>
		<meta?charset="utf-8">
		<title></title>
		<script>
			function?count(){
				var?oTxt1=document.getElemnetById("txt1").value;
				var?oTxt2=document.getElemnetById("txt2").value;
				var?oSlt=document.getElemnetById("select").value;
				var?result="";
				switch(oSlt)
				{
					case?"+":
						result=parseFloat(oTxt1)+parseFloat(oTxt2);
						break;
					case?"-":
						result=parseFloat(oTxt1)-parseFloat(oTxt2);
						break;
					case?"*":
						result=parseFloat(oTxt1)*parseFloat(oTxt2);
						break;
					default:
					????result=parseFloat(oTxt1)/parseFloat(oTxt2);
				}
				document.getElemnetById("fruit").value=result;
			}
		</script>
	</head>
	<body>
			<input?type="text"?id="txt1">
			<select?name=""?id="select">
				<option?value="+">+</option>
				<option?value="-">-</option>
				<option?value="*">×</option>
				<option?value="/">÷</option>
			</select>
			<input?type="text"?id="txt2">
			<input?type="button"?value="="?onclick="count()">
			<input?type="text"?id="fruit">
	</body>
</html>