Facebook Requests Dialog on Mobile failed

Here is my source code:

FB.ui({method: 'apprequests', to: fbId, message: "hello"}, function(resp){
   if(resp.request_ids){
      $('#req-id').val(resp.request_ids);
        $('form').submit();
   } else {
       return false;
   }
});

And here is what I get when I run it in a browser with User Agent set to iPhone:

An error occurred. Please try again later.

It also popup a window to display the message which is not wanted. I've tried to add "display:touch" parameter without any fortune.

Did anyone encountered this before?

Thanks, Green

Facebook Requests dialog is not available on mobile at this time. We are working on a mobile version. Please follow our blog to stay updated on when this launches.

Requests is now available on mobile. For more information see:

https://developers.facebook.com/docs/guides/mobile/web/

set useragent as it is a desktop browser and makes facebook be happy