(function($) {
            $.fn.spinner = function() {
                this.each(function() {
                    var el = $(this);
                    
                    // add elements
                    el.wrap('<span id="'+$(this).attr("id")+'" class="spinner"></span>');     
                    el.removeAttr("id"); 
                    el.before('<span class="sub">-</span>');
                    el.after('<span class="add">+</span>');
                    
                    // substract
                    el.parent().on('click', '.sub', function () {
                        if (el.val() > parseInt(el.attr('min')))
                            el.val( function(i, oldval) { return --oldval; }); 
                        el.trigger("change");  
                    });
                    
                    // increment
                    el.parent().on('click', '.add', function () {
                        if (el.val() < parseInt(el.attr('max')))
                            el.val( function(i, oldval) { return ++oldval; }); 
                        el.trigger("change"); 
                    });
                });
            };
        })(jQuery);