JavaScript undefined error in VS

Question

Taking a online course at udemy on JavaScript. Trying to code what I learned. I'm getting a undefined error. Visual Studio 2012 Pro saying the code is find but when I run the code I get the error.

        <script type="text/javascript">
        var numericalGrade = 82;
        var letterGrade;
        function myResaults() {
            document.write("Your score is " + numericalGrade + "%. Your grade will be a " + letterGrade + ".<br />");
        }

        if (numericalGrade >= 90) {
            letterGrade = "A";
            document.write(myResaults() + " Excellent, you passed this course with flying colors...");
        }

        else if (numericalGrade >= 80) {
            letterGrade = "B";
            document.write(myResaults() + " Excellent, you passed this course with a great grade..");

        }
        else if (numericalGrade >= 70) {
            letterGrade = "C";
            document.write(myResaults() + " Congratulations, you passed this course...");

        }
        else if (numericalGrade >= 60) {
            letterGrade = "D";
            document.write(myResaults() + " You revived a grade that will not permit you to pass this course. You can retake this course at a later date.");

        }
        else {
            letterGrade = "F";
            document.write(myResaults() + "You failed this course. You can retake this course at a later date.");

        }
    </script>

So what am I doing wrong. I'm very new at JavaScript coding.

myResaults() returns undefined since it has no return statement. When you do myResaults() + "" you are concatenating undefined to a string, so you see undefined. — gen_Eric
– gen_Eric, Commented Aug 16, 2013 at 20:10

j08691 · Accepted Answer · 2013-08-16 20:10:16Z

3

Your function needs to return a value, but since it wasn't you were getting undefined instead.

Change:

function myResaults() {
    document.write("Your score is " + numericalGrade + "%. Your grade will be a " + letterGrade + ".<br />");
}

to

function myResaults() {
    return "Your score is " + numericalGrade + "%. Your grade will be a " + letterGrade + ".<br />";
}

answered Aug 16, 2013 at 20:10

j08691

208k33 gold badges269 silver badges281 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Michael Over a year ago

Thanks, it work. I have no clue what return does. Maybe further in the course videos, the instructor will explain what return does. Thanks again.

j08691 Over a year ago

Return does pretty much that, specifies a value to be returned to whatever called the function. See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…. As the MDN docs show, "The expression to return. If omitted, undefined is returned instead."

Collectives™ on Stack Overflow

JavaScript undefined error in VS

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related