Question

I have a simple function which only returns a translated message from the server to the client. But the result shows undefined, when I pass the result into a var.

function MessageNoResult() {
  $.ajax(
  {
    type: "POST",
    async: true,
    url: '<%= ResolveUrl("~/WebMethods.aspx/MessageNoResult") %>',
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function(msg) {
      return msg.d;
    }
  });
}

Result –> Undefined (bad)

var message = MessageNoResult();
alert(message); 

When I look into the Headers it gives me:

Server  ASP.NET Development Server/9.0.0.0
Date    Wed, 09 Nov 2011 09:01:31 GMT
X-AspNet-Version    2.0.50727
Cache-Control   private, max-age=0
Content-Type    application/json; charset=utf-8
Content-Length  24
Connection  Close

Response {"d":"No search result"}
JSON d "No search result"

Why do I still get an undefined result?

Answer 1

You can pass a callback function to the MessageNoResult function

function MessageNoResult(callback) {
  $.ajax(
  {
    type: "POST",
    async: true,
    url: '<%= ResolveUrl("~/WebMethods.aspx/MessageNoResult") %>',
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function(msg) {
      callback(msg);
    }
  });
}

And then call:

MessageNoResult(function(msg) {
    alert(msg.d);
});