Question

Thanks for taking time to review this question. I’ve been trying to fix a problem for one or two hours with no success…

I have a web page that sets a JavaScript variable based on the response from a function:

grade = getScore(questionAnswer, userAnswer, questionType);

(userAnswer is the user’s answer to a question and is retrieved from a textarea)

Here is getScore:

function getScore(questionAnswer, userAnswer, questionType) {

    switch(questionType) {
        case 'multiplechoice':
            return scoreMC(questionAnswer, userAnswer);
        break;

        case 'usertypesanswer':
            return scoreTA(questionAnswer, userAnswer);         
        break;

        default:
            return 0
    }   

}

The functions for scoreMC and scoreTA have been tested thoroughly and work great. The issue is that if a user’s answer is not formatted correctly, scoreMC or scoreTA will return false. Otherwise it returns the values score and msg. However, instead of getting a “false” value for “grade” when I set the value of the grade variable based on the getScore function, I get “undefined”. (We have no problems when the user response validates properly.)

After setting “grade”, I have tried to check if any part of it is undefined:

if(typeof(grade.score) !== undefined)

I do not understand why, but even when I see “undefined” in my Firebug console, grade.score passes this check…

Does anyone see what I am doing wrong? Thank you very much for your assistance. I have a lot to learn about JavaScript.

Answer 1

if(typeof(grade.score) !== undefined)

can be

if(grade.score && grade.score !== false) // if I understand your question 

or

if(typeof(grade.score) !== "undefined")

typeof returns a string