[jQuery] problem with object response

[Sebastián V. Würtz]

How i can handle with jquery the "uncaught exception: [object Object]" 
firefox message when theres no answer from a query (via json in my case)?

      $.ajax({
          url: "weather.php",
          action: "get_weather",
          dataType: 'json',
          success: function(json){
               ....
               do something
               ....
            },
           error: function ( request, errtype, e ) {
               alert ( 'An error occurred while loading this report. ');
           },
      });

Im using $.ajaxSetup( { timeout: 2000 } ); beacause the php sometimes 
dosnt response.