I found the problem:
Old versions of Opera browsers have functions to save and change website source (or something like this).
in the source of my quiz page is written:
<div class=”wpProQuiz_quizAnker” style=”display: none;”></div>
</div>
<script type=”text/javascript”>
jQuery(document).ready(function($) {
$(‘#wpProQuiz_1’).wpProQuizFront({
quizId: 1,
mode: 2,
timelimit: 180,
resultsGrade: [0],
bo: 22595,
qpp: 0,
formPos: 0,
lbn: “Finish quiz” });
});
</script>
With Opera it is possible to change 180 seconds limit and have more time.
How can I solve this?