title: jQuery getJSON response null for Firefox, works for IE
body: <pre><code>$.getJSON(service + "/GetJobTags", 
      { tag: "a" }, 
      function(json) {
          $.each(json, function(i,val) { 
              alert(val.Title); 
          }); 
       });
  </code></pre>
  
  <p>It calls:</p>
  
  <p><a href="http://127.0.0.1:20087/ClientService.svc/GetJobTags?tag=a" rel="nofollow noreferrer">http://127.0.0.1:20087/ClientService.svc/GetJobTags?tag=a</a></p>
  
  <p>This is probably of note, the service is running on a different port to the client application, which is on:</p>
  
  <p><a href="http://127.0.0.1:32017/index.htm" rel="nofollow noreferrer">http://127.0.0.1:32017/index.htm</a></p>
  
  <p>Firefox says HTTP 200 OK but the response data is null (and it highlights in red in Firebug). In IE it works fine, and the server is returning json.</p>
  
  <p>Is this a permissions problem? Do I need to use JSONP?</p>