AAnswers to Exercises

This appendix provides the answers to the questions you find at the end of each chapter in this book.

CHAPTER 2

Exercise 1 Question

Write a JavaScript program to convert degrees centigrade into degrees Fahrenheit, and to write the result to the page in a descriptive sentence. The JavaScript equation for Fahrenheit to centigrade is as follows:

degFahren = 9 / 5 * degCent + 32

Exercise 1 Solution

<!DOCTYPE html>

<html lang="en">
<head>
    <title>Chapter 2: Question 1</title>
</head>
<body>
    <script>
        var degCent = prompt("Enter the degrees in centigrade", 0);
        var degFahren = 9 / 5 * degCent + 32;

        document.write(degCent + " degrees centigrade is " + degFahren +
           " degrees Fahrenheit");
    </script>
</body>
</html>

Save this as ch2_question1.html.

Exercise 2 Question

The following code uses the prompt() function to get two numbers from the user. It then adds those two numbers and writes the result to the page:

<!DOCTYPE html>

<html lang="en">
<head>
    <title>Chapter 2, Question 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>

However, if you try out the code, you’ll discover that it doesn’t work. Why not? Change the code so that it does work.

Exercise 2 Solution

The data that the prompt() actually obtains is a string. ...

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