My solution to this challenge - based on my current JS learning state

/*
JavaScript course by Dave Farland on Treehouse.com
Author of this Code: Saskia Lund
Task: Quiz Challenge
URL: https://teamtreehouse.com/library/javascript-loops-arrays-and-objects/tracking-multiple-items-with-arrays/build-a-quiz-challenge-part-1
Date: June 11, 2015
*/

var correctCount = 0; // stores the number of correct answers the users provide. 
var answer; // stores the user's answer. 
var correctAnswer = []; // stores the correct answers and matching questions
var wrongAnswer = []; // stores wrong answer and matching questions

function print(message) {
  document.write(message);
}

// array provides all quiz questions and answers
var quiz = [
    [ "What's the current US president's first name?", 'barack' ],
    [ 'Which film dog is named after a famous deaf composer and musician?', 'beethoven' ],
    [ 'Where do the best soccer players come from?', 'germany' ],
    [ 'How many toes do we have?', '20' ],
    [ 'Who is playing the main male act in the movie "Braveheart"?', 'mel gibson' ]
];

// cycle through the quiz array and store the user input in the corresponding arrays ans variables
for ( var i = 0; i < quiz.length; i += 1 ) {
    answer = prompt(quiz[i][0]);
    if ( answer.toLowerCase() === quiz[i][1] ) {
        correctAnswer.push('<li>' + quiz[i][0] + '<br>Your answer: ' + answer + '</li>');
        correctCount += 1;
    } else if ( answer.toLowerCase() !== quiz[i][1] ) {
        wrongAnswer.push( '<li>' + quiz[i][0] + '<br>Correct answer would have been: ' + quiz[i][1] + ' </li>' );
        }
}

// collect the answers for web output
var outputCorrectAnswer = correctAnswer.join(' ');
var outputWrongAnswer = wrongAnswer.join(' ');

// Let's tell the user his results
print( '<p>You got ' + correctCount + ' question(s) right.<br></p>' );
print( '<p>You got these questions correct:</p><ol>' + outputCorrectAnswer + '</ol><br>' );
if (wrongAnswer.length === 0) {
    print('');
} else {
print( '<p>You got these questions wrong:</p><ol>' + outputWrongAnswer + '</ol>'  );
}