Getting XML back from a web service when it should be JSON

[Idzevdttu]

I am a noob to ASP.NET/C#. I am trying to use a web service to return a JSON object from the database. I am getting an error in Firebug that I am creating a circular reference. The stack trace is in JSON format. When I view the web service directly in the browser, it is returning valid XML for some strange reason. Here is my web service.\[code\][WebMethod][ScriptMethod(ResponseFormat = ResponseFormat.Json)]public DataSet Posts() { string connString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["XXX"].ConnectionString; SqlConnection conn = new SqlConnection(connString); string sql = "SELECT * FROM Posts"; SqlDataAdapter sda = new SqlDataAdapter(sql, conn); DataSet ds = new DataSet(); sda.Fill(ds); return ds;}\[/code\]I'm new to C# so I don't know if this is written correctly. What I want is a DataSet in JSON format. Am I doing this correctly? Here is the jQuery that is calling the web service. \[code\]<script> $(function () { $.ajax({ type: "POST", url: "WebServices/MessageBoard.asmx/Posts", data: "{}", contentType: "application/json; charset=utf-8", dataType: "json", success: function(data) { console.log(data) }, failure: function (msg) { //alert(msg); } }); });</script>\[/code\]