This issue may occur due to a temporary error on your desktop. If the game keeps freezing, please follow the steps below to resolve the issue:
1. Make sure that you use the latest version of your browser. Please click the following link for more information about your browser: https://www.whatismybrowser.com
2. Clear out your cache and cookies (this will log you out of Facebook).
Refer to the links below for instruction on clearing out your browsing history depending on your browser. Clearing the cache and cookies will allow the page to load faster.
3. Make sure that you do not have other browser tabs/windows or other application running while playing the game. Having multiple programs running will decrease the amount of usable memory, and cause hindered performance.