沒有結果輸出？
<!DOCTYPE html>
<html>
<head>
<title> 事件</title> ?
<script type="text/javascript">
function count(){
//獲取第一個輸入框的值
var t1 = document.getElementById("txt1").value;
????//獲取第二個輸入框的值
????var t2 = document.getElementById("txt2").value;
????//獲取選擇框的值
????var o1 = 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
????
//設置結果輸入框的值
var r1 = " ";
switch (o1){
case "+":
r1 = parseInt(t1) + parseInt(t2);
break;
case "-":
r1 = parseInt(t1) - parseInt(t2);
break;
case "*":
r1 = parseInt(t1) * parseInt(t2);
break;
case "/":
r1 = parseInt(t1) / parseInt(t2);
break;
}
document.getElentById("fruit") = r1;
}
</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>
2018-06-14
document.getElentById("fruit") = r1;應該是document.getElentById("fruit").value = r1;