JS中的计算器

Question

我试图用JS制作一个非常简单的基本计算器。 对于计算器的“加法”部分，放入的数字将无法正确添加...例如：12 + 12表示为“1212”而不是24或6 + 15表示为“615”而不是21表示有谁告诉我为什么？

<!DOCTYPE html>
<html>
<head>
<button onclick="Divide()">Divide</button> </br>
<button onclick="Multiply()">Multiply</button> </br>
<button onclick="Add()">Add</button> </br> 
<button onclick="Subtract()">Subtract</button> </br>
    <script>
    function Divide (){
        var dividend = prompt("What is the dividend?")
        var divisor = prompt("What is the divisor")
        var answer = prompt(dividend / divisor)
    }
    function Multiply (){
        var Number1 = prompt("What is the first number")
        var Number2 = prompt("What is the second number")
        var answer = prompt(Number1 * Number2)
    }
        function Subtract (){
        var Number1 = prompt("What is the first number")
        var Number2 = prompt("What is the second number")
        var answer = prompt(Number1 - Number2)
    }
    function Add (){
        var Number1 = prompt("What is the first number")
        var Number2 = prompt("What is the second number")
        var answer = prompt(Number1 + Number2) 
    }

</script>


</head>
<body>

</body>
</html>

Answer 1

Javascript将用户输入作为字符串数据。 +符号连接字符串。 另外，您希望使用parseInt（）将字符串数据转换为整数：

var answer = prompt(parseInt(Number1) + parseInt(Number2));