[jQuery] getJSON callback? does not work with querystring param

[expresso]

This works fine:

            $.getJSON("http://localhost:59396/xxxWeb/
CarouselHandler.ashx?action=getproducts&ids=" + ids,
                function(data) {

                    carousel.size(allProductIDs.length);

                    if (numberOfImagesLeftToShow <
numberOfImagesToDisplay) {
                        first += (numberOfImagesToDisplay -
numberOfImagesLeftToShow);
                    }

                    var d = 0;
                    for (var i = first; i <= last; i++) {

                        if (d != undefined) {
                            // add data using index of the array
returned by JSON (which starts at 0)
                            carousel.add(i, decode(data[d].ImageTag));
                        }

                        // set to last ProductID showing in Carousel
                        if (i == last) { lastProductID = parseFloat
(data[d].ProductID); }

                        d++;
                    }
                }
            );

This does not work, I get no pictures rendered after trying to add the
&format=json&jsoncallback=? :

            $.getJSON("http://localhost:59396/xxxWeb/
CarouselHandler.ashx?action=getproducts&ids=" + ids +
"&format=json&jsoncallback=?",
                function(data) {

                    carousel.size(allProductIDs.length);

                    if (numberOfImagesLeftToShow <
numberOfImagesToDisplay) {
                        first += (numberOfImagesToDisplay -
numberOfImagesLeftToShow);
                    }

                    var d = 0;
                    for (var i = first; i <= last; i++) {

                        if (d != undefined) {
                            // add data using index of the array
returned by JSON (which starts at 0)
                            carousel.add(i, decode(data[d].ImageTag));
                        }

                        // set to last ProductID showing in Carousel
                        if (i == last) { lastProductID = parseFloat
(data[d].ProductID); }

                        d++;
                    }
                }
            );

Same for here, calling to our dev server.

$.getJSON("http://xxxdev/xxx/CarouselHandler.ashx?
action=getproducts&ids=" + ids + "&format=json&jsoncallback=?",
                function(data) {

No idea why.  No errors, nothing.