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哪里錯了？

<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
?????var?a=document.getElementById("txt1").value
?????var?b=document.getElementById("txt2").value
????var?c=document.getElementById("select").value
????var?result;
????switch(select)
????{case?"+":result=a+b;break;
?????case?"-":result=a-b;break;
?????case?"*":result=a*b;break;
?????case?"/":result=a/b;break;?
?????document.getElementById("fruit").value=result;}
??????}????
??</script>?
?</head>?
?<body>
???<input?type='text'?id='txt1'?/>?
???<select?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>

qq_小白_7

2015-06-22

源自：JavaScript進階篇 6-11

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1 回答

康振寧
2015-06-23

function?count(){
		var?a=document.getElementById("txt1").value*1;
		var?b=document.getElementById("txt2").value*1;
		var?c=document.getElementById("select").value;
		var?result;
		switch(c){
			case?"+":result=a+b;break;
			case?"-":result=a-b;break;
			case?"*":result=a*b;break;
			case?"/":result=a/b;break;?
		}
		document.getElementById("fruit").value=result;
	}