I am a developer and have recently noticed this issue with Firefox. I've tried in FF version 26 and 27. Also, I've tried this on different flash player versions. I'm able to see the same confirmation dialogs in Chrome but in Firefox it gets stuck on loading screen. Also, the callback function is not getting called so it makes difficult to see the error.
I'm using the same code in both Chrome and Firefox. FB.ui({method: 'apprequests', message: 'My Great Request', to: {user-ids} }, requestCallback);
I've attached a snapshot of the FB dialog where it gets stuck. http://screencast.com/t/cqU8LFMpL
Can someone please help me figure out the issue ?
nice to know that is not only a my problem, I just posted the exact same error here
Method FB.ui loads forever when called on Firefox and Internet Explorer
来源：https://stackoverflow.com/questions/22389148/facebook-request-prompt-not-loading-for-game-in-firefox