ASMX web Service call from a different domain using Jquery

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Ajax

jQuery

webservice

Hi,

I have a very simple asmx webservice in one Visual Studio project

[WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    [System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebService
    {

        [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
        public string HelloWorld()
        {
            return "helloworld";
        }

    }

I am trying to call this web service from another project in Visual Studio using ajax call

$(document).ready(function () {

            $.ajax({
                url: "http://localhost:17889/Service1.asmx/HelloWorld",
                type: "POST",
                dataType: "jsonp",
                crossDomain:true,
                contentType: "application/json;charset=utf-8",
                
                success: function (d) {

                    alert("success");
                    alert(d.data);

                },
                error: function (xhr, status, error) {


                    console.log(xhr.responseText);
                    console.log(status);
                    console.log(error);
                   
                }
            });

        });

my web.config looks like this

<webServices>
      <protocols>
        <add name="HttpGet"/>
        <add name="HttpPost"/>
      </protocols>
      </webServices>

<httpProtocol>
       <customHeaders>
         <add name="Access-Control-Allow-Origin" value="http://localhost:17889" />
         <add name="Access-Control-Allow-Headers" value="Origin, X-Requested-With, Content-Type, Accept" />
       </customHeaders>

     </httpProtocol>

the errors are
Uncaught SyntaxError: Unexpected token <<br mode="hold" />

undefined

parsererror
Error: jQuery19004053758140653372_1453581966937 was not called(…)

what's wrong with my approach? I have gone through a lot of posts, but still struggling to get a proper solution.
Please suggest.