Having multiple quizzes in a page

[Aleyasen]

I tried to use multipe quizzes in the page that user can select between those by a drop-down menu.

$(".quizpicker").on('change', function () {
        var selected = $(this).val();
        quizJSON = window[selected + "JSON"];
        $('#slickQuiz').slickQuiz();
    });

when I set quizJSON and call the slickQuiz() method nothing happend. I'll be thankful if someone can guide me.
This is the html part.

<div id="slickQuiz">
    <br>
    <h3 class="quizName"><!-- where the quiz name goes --></h3>

    <div class="quizArea">
        <div class="quizHeader">
            <!-- where the quiz main copy goes -->

            <a class="button startQuiz" href="#">Get Started!</a>
        </div>

        <!-- where the quiz gets built -->
    </div>

    <div class="quizResults">
        <h3 class="quizScore">You Scored: <span><!-- where the quiz score goes --></span></h3>

        <h3 class="quizLevel"><strong>Ranking:</strong> <span><!-- where the quiz ranking level goes --></span></h3>

        <div class="quizResultsCopy">
            <!-- where the quiz result copy goes -->
        </div>
    </div>
</div>