title: jQuery AJAX appending to Json return data "d:null"
body: <p>Hey all I am getting an odd return from my callback when using the AJAX POST method to call my webservice.</p>
  
  <p>The webservice is sending the JSON back like this:</p>
  
  <pre><code>Dim ser As New System.Web.Script.Serialization.JavaScriptSerializer()
  Dim strResponse As String = ser.Serialize(results)
  
  Context.Response.Clear()
  Context.Response.ContentType = "application/json"
  Context.Response.AddHeader("content-length", strResponse.Length.ToString())
  Context.Response.Write(strResponse)
  HttpContext.Current.ApplicationInstance.CompleteRequest()
  </code></pre>
  
  <p>The value of <strong>strResponse</strong> above is:</p>
  
  <pre><code>"[{\"Column1\":\"0589S2F\"},{\"Column1\":\"53699FNS\"},{\"Column1\":\"C38VVFD\"},{\"Column1\":\"LFD55F\"},{\"Column1\":\"2ERfG\"},{\"Column1\":\"0079\"},{\"Column1\":\"2054\"},{\"Column1\":\"054FGW\"}]"
  </code></pre>
  
  <p>And for some reason my ajax returns <strong>200</strong> <strong>OK</strong> yet still goes into the <strong>ERROR</strong> logic with an error message of:</p>
  
  <pre><code>ERROR: "[{\"Column1\":\"0589S2F\"},{\"Column1\":\"53699FNS\"},{\"Column1\":\"C38VVFD\"},{\"Column1\":\"LFD55F\"},{\"Column1\":\"2ERfG\"},{\"Column1\":\"0079\"},{\"Column1\":\"2054\"},{\"Column1\":\"054FGW\"}]"{"d":null}
  </code></pre>
  
  <p>Notice how it appends the <strong>{"d":null}</strong> to the end of my request... Where is that coming from since I am not sending anything like that back in the  <strong>strResponse</strong>???</p>
  
  <p>My ajax request code:</p>
  
  <pre><code>var sqlQ = "SELECT TOP 50 LTRIM(RTRIM(REPLACE(OID, ' ', ''))) FROM vwPSDAT WHERE OID != ''";
  
  $.ajax({
       type: 'POST',
       contentType: 'application/json; charset=utf-8',
       dataType: 'json',
       url: 'http://zzzz/Service1.asmx/theQ',
       data: JSON.stringify({ qString: [sqlQ] }),
       async: true,
       cache: false,
       success: function (data) {
          var obj = jQuery.parseJSON(data);
          console.log('done!');                  
       },
       error: function (XMLHttpRequest, textStatus, errorThrown) {
          console.log('ERROR: ' + XMLHttpRequest.responseText);
       }
  });
  </code></pre>