Ajax request returns 200 OK, but an error event is fired instead of success

jQuery.ajax attempts to convert the response body depending on the specified dataType parameter or the Content-Type header sent by the server. If the conversion fails (e.g. if the JSON/XML is invalid), the error callback is fired.

Your AJAX code contains:

dataType: "json"

In this case jQuery:

Evaluates the response as JSON and returns a JavaScript object. […] The JSON data is parsed in a strict manner; any malformed JSON is rejected and a parse error is thrown. […] an empty response is also rejected; the server should return a response of null or {} instead.

Your server-side code returns HTML snippet with 200 OK status. jQuery was expecting valid JSON and therefore fires the error callback complaining about parseerror.

The solution is to remove the dataType parameter from your jQuery code and make the server-side code return:

Content-Type: application/javascriptalert("Record Deleted");

But I would rather suggest returning a JSON response and display the message inside the success callback:

Content-Type: application/json{"message": "Record deleted"}

You simply have to remove the dataType: "json" in your AJAX call

$.ajax({    type: 'POST',    url: 'Jqueryoperation.aspx?Operation=DeleteRow',    contentType: 'application/json; charset=utf-8',    data: json,    dataType: 'json', //**** REMOVE THIS LINE ****//    cache: false,    success: AjaxSucceeded,    error: AjaxFailed});

I've had some good luck with using multiple, space-separated dataTypes (jQuery 1.5+). As in:

$.ajax({    type: 'POST',    url: 'Jqueryoperation.aspx?Operation=DeleteRow',    contentType: 'application/json; charset=utf-8',    data: json,    dataType: 'text json',    cache: false,    success: AjaxSucceeded,    error: AjaxFailed});