var activePage = 0,
    pages = document.querySelectorAll('.quiz-page'),
    answers = [];

function goToNext(buttonObj)
{
    var questions = document.getElementsByName('question' + activePage),
        value = -1;

    for(var i = 0; i < questions.length; i++)
        if(questions[i].checked)
            value = questions[i].value;

    if(value < 0)
    {
        alert('Please choose one value!');
        return;
    }
    else
        // save the answer in array
        answers[activePage] = value;

    activePage++;

    for(var i = 0; i < pages.length; i++)
        pages[i].style.display = 'none';
    
    if(activePage < pages.length)
        pages[activePage].style.display = 'block';
    else
    {
        buttonObj.style.display = 'none';
        sendResultsToServer();
    }

    if(activePage == pages.length - 1)
        buttonObj.value = 'Get Results';
}

function sendResultsToServer()
{
    var strAllAnswers = answers.join(',');
    console.log('Answers indexes (one on each page): ' + strAllAnswers);

    //TODO: Send results to server using AJAX
    //... your AJAX code ...

    // Following example of code is for server side checking of results.
    // If you want you could do this checking of results on the
    // client side, but somebody could know all the correct
    // results if you do it on the client side. Be careful!

    var questions =
    [
        {
            question: 'True or false: 3 + 3 = 6?',
            answers: ['False','True'],
            correctAnswer: 1
        },
        {
            question: 'What sound does a dog make?',
            answers: ['Meow','Mooo','Woof'],
            correctAnswer: 2
        },
        {
            question: 'Which from movie names below is a science fiction movie?',
            answers: ['Star Wars','Planet of the Apes','Lion King','Shrek'],
            correctAnswer: 1
        },
    ];

    var arAllAnswers = strAllAnswers.split(',');
    var result = '<h3>Results</h3>';

    for(var i = 0; i < questions.length; i++)
    {
        result += '<p><b>' + questions[i].question + '</b></p>';
        result += 'Your answer was: ' + questions[i].answers[arAllAnswers[i]] + '<br>';
        result += 'Correct answer is: ' + questions[i].answers[questions[i].correctAnswer];
    }

    var resultPage = document.querySelector('#result');
    resultPage.innerHTML = result;
    resultPage.style.display = 'block';
}

label{cursor:pointer}

<div class="quiz-page">
    <p><b>Question 1 of 3.</b> True or false: 3 + 3 = 6?</p>
    <label><input type="radio" name="question0" value="0">False</label><br>
    <label><input type="radio" name="question0" value="1">True</label> 
</div>
<div class="quiz-page" style="display:none">
    <p><b>Question 2 of 3.</b> What sound does a dog make?</p>
    <label><input type="radio" name="question1" value="0">Meow</label><br>
    <label><input type="radio" name="question1" value="1">Mooo</label><br>
    <label><input type="radio" name="question1" value="2">Woof</label>
</div>
<div class="quiz-page" style="display:none">
    <p><b>Question 3 of 3.</b> Which from movie names below is a science fiction movie?</p>
    <label><input type="radio" name="question2" value="0">Star Wars</label><br>
    <label><input type="radio" name="question2" value="1">Planet of the Apes</label><br>
    <label><input type="radio" name="question2" value="2">Lion King</label><br>
    <label><input type="radio" name="question2" value="3">Shrek</label>
</div>
<div id="result" style="display:none"></div>
<br>
<input type="button" value="Next" onclick="goToNext(this)">