I have some html like this:
Volume =
To get the id of the parent div:
$(buttonSelector).parents('div:eq(0)').attr('id');
Also, you can refactor your code quite a bit:
$('button').click( function() {
var correct = Number($(this).attr('rel'));
validate(Number($(this).siblings('input').val()), correct);
$(this).parents('div:eq(0)').html(feedback);
});
Now there is no need for a button-class
explanation
eq(0), means that you will select one element from the jQuery object, in this case element 0, thus the first element. http://docs.jquery.com/Selectors/eq#index
$(selector).siblings(siblingsSelector) will select all siblings (elements with the same parent) that match the siblingsSelector http://docs.jquery.com/Traversing/siblings#expr
$(selector).parents(parentsSelector) will select all parents of the elements matched by selector that match the parent selector. http://docs.jquery.com/Traversing/parents#expr
Thus: $(selector).parents('div:eq(0)'); will match the first parent div of the elements matched by selector.
You should have a look at the jQuery docs, particularly selectors and traversing: