function updateExamTimer() {

    var timeLeft = EXAM_TIME_LEFT - elapsedTime;
    elapsedTime += 1;

    var minutes = Math.floor(timeLeft / 60);
    var seconds = timeLeft % 60;
    var hours = Math.floor(minutes / 60);
    var minutes = minutes % 60;

    if (hours < 10) { hours = '0' + hours; }
    if (minutes < 10) { minutes = '0' + minutes; }
    if (seconds < 10) { seconds = '0' + seconds; }


    if (timeLeft <= 0) {

        alert('Sizning imtihon topshirish muddatingiz yakunlandi.');

        // If we're in ajax mode, submit via ajax - otherwise, redirect to the completion page
        if (jQuery('#exam-ui').length) {
            finishExam(false);
        } else {
            document.location.href = 'complete.php?id=' + EXAM_REQUEST_ID;
        }

    } else {
        jQuery('#exam-time-left').val(hours + ':' + minutes + ':' + seconds);
   if(navigator.onLine) {
    // Устройство в интернете
setTimeout('updateExamTimer()', 1000);
} else {
    // Устройство не подключено к интернету
}
    }

}