The code:

$('input.media-checkbox').live('click', function(e){

    e.preventDefault();
    var that = $(this);

    if (that.attr('checked') == 'checked'){

        var m = that.attr('media');
        var mid = 'verify_' + m;
        that.parents('div.state-container').find('ul.' + mid).remove();
        that.attr('checked', false);
    } else {

        var url = AJAX_URL;

        $.ajax({
           type: 'GET',
           url: url,
           dataType: 'html',
           success: function(data){

                that.parents('li').siblings('li.verification').children('div.media-verification').append(data).fadeIn(500);
                that.attr('checked', 'checked');
           }
        }); 
    }

    return false;
});

I am ajaxing in a form, then firing the click event on relevant checkboxes to ajax in another partial if necessary. The form is inserted nicely, and the click events are fired, checking the boxes that need to be checked and firing the second ajax, since the checked attribute of the checkbox was initially false.

What's curdling my cheese is if I UNCHECK one of those boxes. Despite e.preventDefault(), the checked attribute is set to false BEFORE the test, so the if statement always executes the else statement. I've also tried this with $.is(':checked'), so I'm completely baffled.

It appears that unchecked -> checked state reads the original state, but checked -> unchecked doesn't. Any help?