I have a form that looks like this:
I don't get how return false and preventDefault failed to do their job. Maybe try replacing the image buttons with linked images:
$('#vote_form > a').click(function(e) {
e.preventDefault();
//one way to know which image was clicked
alert($(this).attr('class'));
$.post(...
});
You can always ensure that a form does not submit by binding to the submit event, e.g.:
$('#vote_form').submit(function() {
return false;
});