Question

I’m using jQuery’s form plugin (as suggested in a number of threads like this one) to make an Ajax post to a .NET MVC controller and consume the JSON I get back. It works just fine in Chrome, but in some other browsers, including Firefox 3, the form submit results in a “Save or Open this file” dialog box. The JavaScript looks like:

var options = {
            dataType: "json",
            clearForm: true,
            beforeSubmit: hideUpdateField,
            success: handleNewsPostSuccess
        };

        $('div#Updates form').ajaxForm(options);

and meat of the controller response is:

Object response = new { html = RenderPartialViewToString("DisplayNewsPost", np), newpoints = points.ToString() };
return Json(response, "application/json; charset=utf-8");

What am I missing? It’s like the submit event isn’t getting attached in Firefox and the other problem browsers. I tried making my own submit action using ajaxSubmit instead with a return false in it, but no difference.

Answer 1

Use different MIME type for response; simple text/plain should work. I believe FF is confused by unknown application/* MIME type and thus assumes it’s some application-specific data that are best downloaded as separate file.

Alternatively, you can experiment with Content-Disposition header, setting it to inline. Firefox should be obeying it, but IIRC there might be some problems with it on IE.