Question

removeClass doesn’t remove the class selected from div.upvote in the js below, but addClass() works fine. Why is that?

$(document).ready(function () {
"use strict";

    $('div.upvote').click(function () {
        var id = $(this).parents('li.book').attr('id');
        var vote_type = 'up';

        if ($(this).hasClass('selected')) {
            var vote_action = 'recall-vote';
            $.post('/b/vote/', {id: id, type: vote_type, action: vote_action}, function (response) {
                if ($.isNumeric(response)) {
                    $('li#' + id)
                        .find('div.upvote')
                        .removeClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            });
        } else {
            var vote_action = 'vote';
            $.post('/b/vote/', {id: id, type: vote_type, action: vote_action}, function (response) {
                if ($.isNumeric(response)) {
                    $('li#' + id)
                        .find('div.upvote')
                        .addClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            });
        }
    });
}

Answer 1

$(document).ready(function () {
    "use strict";

    $('div.upvote').click(function () {
        var id = $(this).parents('li.book').attr('id');
        var vote_type = 'up';


        if ($(this).hasClass('selected')) {
            var vote_action = 'recall-vote';
            (function (response) { // skip ajax, just call success callback
                if ($.isNumeric(response)) {
                    $('li#' + id)
                            .find('div.upvote')
                            .removeClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            }(123)); // fake numeric response
        } else {
            var vote_action = 'vote';
            (function (response) {
                if ($.isNumeric(response)) {
                    $('li#' + id)
                            .find('div.upvote')
                            .addClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            }(123));
        }
    });
}) // ) missed

HTML:

<li id="li-id" class="book">
    <div class="upvote selected">upvote</div>
</li>​

With fake data all works fine. So you have a problem with non-numeric response or with missed )