Prowler,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script src="http://code.jquery.com/jquery-latest.js"></script>
<script>
$(function () {
$('#test').click(function () {
$("div.answers").each(function () {
if (!$('input:checked', this).length) {
alert('Вопрос ' + this.id + ' неотвечен');
}
});
})
})
</script>
</head>
<body>
<div id=6 class="answers">
<input type="radio" name='6' />
<input type="radio" name='6' />
<input type="radio" name='6' />
</div>
<div id=7 class="answers">
<input type="radio" name='7' />
<input type="radio" name='7' />
<input type="radio" name='7' />
<input type="radio" name='7' />
<input type="radio" name='7' />
</div>
<input name="" type="button" value="проверка" id="test">
</body>
</html>