4-8 请老师检查
来源：4-8 编程练习
慕妹6205103
2020-07-09 12:25:46
<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
</head>
<body>
<input type='text' id='num1' />
<select id='operate'>
<option value='+'>+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type='text' id='num2' />
<input type='button' value=' = ' onclick="count()" />
<input type='text' id='result' />
<script type="text/javascript">
function count() {
var num1 = document.getElementById("num1");
var num2 = document.getElementById("num2");
var operate = document.getElementById("operate");
var result = document.getElementById("result");
if (isNaN(num1.value)||isNaN(num2.value)) {
alert("请输入数字");throw new Error("不是数字！");
}
switch(operate.value){
case '+' :
result.value = +num1.value + +num2.value;
break;
case'-':
result.value = num1.value - num2.value;
break;
case'*':
result.value = num1.value * num2.value;
break;
case'/':
result.value = num1.value / num2.value;
break;
}
}
</script>
</body>
</html>
1回答
-
好帮手慕久久
2020-07-09
同学你好，代码正确，很棒，祝学习愉快！
0
相似问题