javascript中的意外输出 [英] Unexpected output in javascript

问题描述

我是javascript的初学者，我得到了意想不到的输出

I am beginner to javascript and i am getting unexpected output

这里是代码

<script type="text/javascript">

        function add(a,b)
        {
            x = a+b;
            return x;
        }
        var num1 = prompt("what is your no.");
        var num2 = prompt("what is another no.")

        alert(add(num1,num2));


    </script>

它应该将输出作为我们在提示时输入的两个数字的总和，但它只是连接两个数字并弹出输出

it should give output as a sum of two number entered by us on prompting but it is simply concatenating the two number and popping the output

推荐答案

这是因为提示符函数返回 String 而不是 Number 。所以你实际做的是请求2个字符串然后连接它们。如果你想将两个数字加在一起，你必须将字符串转换为数字：

This is because the prompt function returns a String and not a Number. So what you're actually doing is to request 2 strings and then concatenate them. If you want to add the two numbers together you'll have to convert the strings to numbers:

var num1 = parseFloat(prompt("what is your no."));
var num2 = parseFloat(prompt("what is another no."));

或更简单：

var num1 = +prompt("what is your no.");
var num2 = +prompt("what is another no.");

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