Question

First time using jquery (using the out of the box 1.4.4 in MVC3 even though its dated).
I am trying to update some elements on the screen as follows,

$(document).ready(function () {
    $.ajax({
        url: '<snip />',
        dataType: 'json',
        success: function (data, textStatus, jqXHR) {
            // <snip />
        },
        error: function (jqXHR, textStatus, errorThrown) {
             // <snip />
        }
    });
 });

This always calls the error function, even though in the jqXHR object I can clearly see the text response

"{
  "DBHealth": "Grey",
  "FSHealth": "Grey",
  "WSHealth": "Grey"
}"

Full HTTP server response is (courtesy of WireShark),

HTTP/1.1 200 OK
Cache-Control: private, s-maxage=0
Content-Type: application/json; charset=utf-8
Server: Microsoft-IIS/7.5
X-AspNetMvc-Version: 3.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Persistent-Auth: true
Date: Thu, 03 May 2012 14:11:23 GMT
Content-Length: 72

{
  "DBHealth": "Grey",
  "FSHealth": "Grey",
  "WSHealth": "Grey"
}

textStatus is error rather than parsererror, so I assume the problem is not my JSON.
errorThrown is null unsurprisingly as its.

Obvious question is, why is it erroring?

Answer 1

Visual Studio was being silly. Restarted the debug session and it succeeded just fine. Didn’t change anything in the javascript or server side Controller.