开始Javascript第2章结束练习2

Question

我正在学习 Beginning Javascript 但无法通过第 2 章完成练习 2。练习是更正这段代码

 <!DOCTYPE html>

<html lang="en">
<head>
    <title>Chapter 2, Finishing exercise 2</title>
</head>
<body>

    <script>
        var firstNumber = prompt("Enter the first number", "");
        var secondNumber = prompt("Enter the second number", "");
        var theTotal = firstNumber + secondNumber;

        document.write(firstNumber + " added to " + secondNumber + " equals " theTotal);

    </script>
</body>
</html>

我可以使用警报获得正确的总数来显示，但是当我删除评论时它不再有效。

<!DOCTYPE html>

<html lang="en">
<head>
    <title>Chapter 2, Finishing exercise 2</title>
</head>
<body>
    <script>
        var firstNumber = prompt("Enter the first number", "");
        var secondNumber = prompt("Enter the second number", "");


        var intFirstNumber = parseInt(firstNumber, 10);
        var intSecondNumber = parseInt(secondNumber, 10);
        var theTotal = intFirstNumber + intSecondNumber;


        alert(theTotal);
        //document.write (intFirstNumber + " added to " + intSecondNumber + " equals " theTotal);

    </script>
</body>
</html>

我无法弄清楚我的 document.write 陈述有什么错误。有什么提示吗？另外还有更优雅的方式来实现我正在做的事情吗？

Answer 1

您需要 "equals" 和 theTotal 之间的另一个 +:

document.write(firstNumber + " added to " + secondNumber + " equals " + theTotal);

在此上下文中，+ 符号表示将其后面的内容连接（附加）到它之前的内容。

进一步阅读：

MDN documentation for string concatenation.

开始Javascript第2章结束练习2

Beginning Javascript Chapter 2 finishing exercise 2

javascript

parseint