(function($){
    $.fn.extend({
        categoryFader: function(options) {
            var defaults={
                fadeOpacityStep : 0.3
            }

            var o = $.extend(defaults, options)

            $(this).live('click', function(){
                val = $(this).val();
                if(this.checked){
                    $('div[rel*='+val+']').each(function(){
                        currOpacity = parseFloat($(this).css('opacity'));
                        $(this).fadeTo("fast", currOpacity+o.fadeOpacityStep);
                        
                    });
                }
                else{
                    $('div[rel*='+val+']').each(function(){
                        currOpacity = $(this).css('opacity');
                        $(this).fadeTo("fast", currOpacity-o.fadeOpacityStep);
                    });
                }

            })
        }
    })
})(jQuery);