我正确地编写了所有内容,但是没有用。我听不懂我没有看到问题,但是仍然无法正常工作。我的英语不太好,所以我无法详细解释。
我只是不知道为什么这不起作用。
function calc() {
var a = parseInt(document.querySelector("#value1").value);
var a = parseInt(document.querySelector("#value2").value);
var op = (document.querySelector("#operator").value);
var calculate;
if (op == "add") {
calculate = a + b;
} else if (op =="min") {
calculate = a - b;
} else if (op =="div") {
calculate = a / b;
} else if (op =="mul") {
calculate = a * b;
}
console.log(calculate);
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<form>
Value 1: <input type="text" id="value1">
<br>
Value 2: <input type="text" id="value2">
Operator:
<select id="operator">
<option value="add">Add</option>
<option value="min">Minus</option>
<option value="div">Divide</option>
<option value="mul">Multiply</option>
</select>
<button type="button" onclick="calc()">Calculate</button>
</form>
</body>
<script src="js/main.js"></script>
</html>
答案 0 :(得分:1)
您缺少在第3行中声明var'b'的信息。正确的代码应为:
var a = parseInt(document.querySelector("#value1").value);
var b = parseInt(document.querySelector("#value2").value);