'invalid label' error when returning JSON form rails controller when Firebug is closed

If I have Fi开发者_如何学运维rebug console open, and return the following in a rails controller in response to an ajax call:

format.json { render :json => Appointment.find_by_id(1) } 

I get an 'invalid label' error. But it works fine it Firebug is closed.

Any ideas???

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What solved it for me was:

jQuery.ajaxSetup({
          jsonp: null,
          jsonpCallback: null
        });

The problem is that the browser treats the json as jsonp and adds a callback to it.

This command solves it (at least for me).

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This seems to be related to using JQuery 1.5. Could you confirm that this doesn't happen with JQuery 1.4.4?

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I concur with Tomer that this is a json-vs-jsonp problem, but his code didn't fix it for me. I fixed it by adding this jQuery code (works in 1.4 and 1.6):

$(function() {
  $.ajaxSetup({
    dataType: 'json'
  });
});