asp.net - How to call external webservice using jquery "jsonp"?

Question

I had a previous question can jquery ajax call external webservice?

and some good developers answered me to use jsonp, but i don't know how to use it, i am trying to call my service using this code:

$.ajax({
            type: "POST",
            url: "http://localhost:1096/MySite/WebService.asmx?callback=?",
            data: "{}",
            contentType: "application/json; charset=utf-8",
            dataType: "jsonp",
            success: function(msg) {alert(msg);}
            });

and this is my service code:

[WebMethod]
public string HelloWorld() {
    return "Hello World " ;
}

anyone have examples or can explain this issue for me?

UPDATE:
I wrote the code again to be like this:

$.getJSON("http://localhost:1096/YourShoppingTest1/WebService.asmx/HelloWorld?jsonp=?",{name:"test"},
    function(data){
    alert(data.x);
    });

and the service like this:

[WebMethod]
public string HelloWorld(string name)
{
    return "( {"x":10 , "y":100} )";
}

But it always give me this error when back: "missing ; before statement [Break on this error] ( {"x":10 , "y":100} )"

and never call the success function, can anyone help with that?

Answer 1

I've had a similiar problem, unfortunately I don't have the code at hand.

From memory:

• Add [ScriptService] as an attribute to your Web Method
• Also change your url to call the HelloWorld procedure.
  Something like http://localhost:1096/MySite/WebService.asmx/HelloWorld?callback

See: What are some good examples of JQuery using JSONP talking to .net? & What is the best way to call a .net webservice using jquery?