You always have the option to deactivate animations and reduce the quality when you’re experiencing any performance issues with your game. This might help with lags and freezes. To do that open the “options”-menu, which can be found in the right upper corner of your screen, select “settings” and untick the box for “animations” and set a lower quality, “medium” or “low” for instance.
In addition it might help to clear the cache and delete the cookies from your browsers to achieve a better performance.