Question

I created an aspx file that act as JSON result.

Response.Clear()
Response.ContentType = "application/json; charset=utf-8"

I have another page (another domain) that read that JSON. But I got syntax error: invalid label when calling the JSON value.

$.getJSON( "http://a.com/json.aspx?format=json&jsoncallback=?" , function(data) {

       alert(data);
    });
  }

Answer 1

You need the server to output JSONP, not JSON. JSONP is different. JSONP is used when the server is on a different domain then the client.

JSONP is actually just a JavaScript file, so it should be served with Content-type: text/javascript. When serving JSONP, you should wrap the JSON in the value of jsoncallback.

So, your web server should output something similar to:

jQuery12345({"name":"joe","age":22})

Where jQuery12345 is the value of the jsoncallback parameter in the query string, which will be automatically set by jQuery.

$.getJSON( "http://a.com/json.aspx?format=json&jsoncallback=?" , function(data) {
    alert(data);
});

jQuery will automatically replace the ? with a value.

More info on JSONP: http://en.wikipedia.org/wiki/JSONP