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                        /前端開發
                        
                            /JavaScript
                        
                        /JavaScript進階篇

給大家參考

<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
???????
????var?txt1=document.getElementById('txt1').value;
????var?txt2=document.getElementById('txt2').value;
????var?oValue=document.getElementById('select').value;
????var?result=0;
????
????switch(oValue)??{
????????case?'+':
????????????result=parseInt(txt1)+parseInt(txt2);
????????????break;
????????case?'-':
????????????result=parseInt(txt1)-parseInt(txt2);
????????????break;
????????case?'*':
????????????result=parseInt(txt1)*parseInt(txt2);
????????????break;
????????case?'/':
????????????result=parseInt(txt1)/parseInt(txt2);????
????????????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()'?/>?<!--通過?=?按鈕來調用創建的函數，得到結果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>