<!DOCTYPE?html>????
<html>????
<head>????
<meta?charset="utf-8">????
<title>?事件</title>??????
<script?type="text/javascript"?>????
function?count(){????
//獲取第一個輸入框的值????
var?txt1=parseInt(document.getElementById('txt1').value);????
//獲取第二個輸入框的值????
var?txt2=parseInt(document.getElementById('txt2').value);????
//獲取選擇框的值????
var?select=parseInt(document.getElementById('select').value);????
//獲取通過下拉框來選擇的值來改變加減乘除的運算法則????
var?result='';????
switch(select){????
case'+':????
result=txt1+txt2;????
break;????
case'-':????
result=txt1-txt2;????
break;????
case'*':????
result=txt1*txt2;????
break;????
case'/':????
result=txt1/txt2;????
break;????
}????
//設置結果輸入框的值????
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>
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