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JavaScript JavaScript Arrays Multidimensional Arrays Improve the Quiz – One Solution

Cory Rhodes
Cory Rhodes
5,096 Points

I am getting 'undefined' as well. I decided to the assignment a little differently; but anyway, here is the code.

const quiz = [

[ "How many stooges does it take to screw in a light bulb?", "A: one", "B: two", "C. three" ],

[ "What's the difference between a cult and a church?", "A: a cult allows gays to join, a church doesn't", "B: a church is a cult", "C: people who go to church go to heaven." ],

[ "What is considerd a healthy sex life?", "A: frequently with one partner", "B: once in a while", "C: frequently, but with a hooker" ]


const answers = [ 'c', 'a', 'c', ];

// 2. Store the number of questions answered correctly

function getResponses(arr) {

let responseList = [];

for ( i = 0; i < arr.length; i++ ) {

//let response;

    responseList.push(prompt(`*** ONLY write the LETTER that corresponds to the answer, WITHOUT periods, commas, etc. ***

    Question #${i + 1}: ${arr[i][0]}



    ${quiz[i][3]}`) );


return responseList;

} const responses = getResponses(quiz);

function getScore(arr1, arr2) {

let score = 0;

for ( i = 0; i < answers.length; i++ ) {

    if ( arr2[i].toLowerCase() === arr1[i] ) {




return score;


const score = getScore(answers, responses);

function recordResponses(arr1, arr2) {

let items = [];

for ( i = 0; i < answers.length; i++ ) {

    if ( arr2[i].toLowerCase() === arr1[i] ) {

        items += `<li>Correct, the answer is ${arr1[i].toUpperCase()}, you answered     


    } else {

        items += `<li>Incorrect, you answered ${arr2[i].toUpperCase()} the correct answer was 




return items;


function congragulate(score) {

let paragraphBuilder;

if ( score === 3 ) {

        paragraphBuilder += ( `<p>You got 100% of the answers correct! Keep up the good work!</p>`);

    } else if ( score === 2 ) {

        paragraphBuilder += ( `<p>Good job! You almost got a perfect score!</p>` );

    } else {

        paragraphBuilder += ( `<p>You did not pass the quiz.  Keep on improving before moving on!</p>` );


return paragraphBuilder;


let html = `

<h1>Here are your Quiz Results</h1>

<h2>You got ${score} out of ${answers.length} answers correct.</h2>



    ${recordResponses(answers, responses)}



document.querySelector('main').innerHTML = html;

1 Answer

Steven Parker
Steven Parker
224,872 Points

In the function "congragulate", you create a new variable named "paragraphBuilder", then a string (one of 3) is added to this variable using the concatenating assignment operator (+=). Since this operation adds onto a string, and since the variable had not yet been given any contents, the value "undefined" will be displayed in front of the string added in.

Using a normal assignment (=) instead of the special one will fix this.

Steven Parker is right, but ultimately, you don't need the paragraphBuilder variable at all. Since you're just returning a string, you could simplify your function like this:

function congragulate(score) {
    if ( score === 3 ) return `<p>You got 100% of the answers correct! Keep up the good work!</p>`;
    if ( score === 2 ) return `<p>Good job! You almost got a perfect score!</p>`;
    return `<p>You did not pass the quiz.  Keep on improving before moving on!</p>`;