It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

If you are having trouble getting the game stable, try disabling the overlay. I was crashing everytime the game launched due to it, and now with it off, the game is stable.

This is only on my Macbook, my PC is fine.