Browsers impose limits on the number of active WebGL contexts. Exceed the limit and the browser will start to dump older contexts. My understanding is that there are limits per domain as well as an overall max.

Two questions:

1. Is there a way to determine how close you are to the limits, i.e., how many active WebGL contexts there are and how many available?
2. I've found scraps of info here and there, but haven't been able to nail down exactly what the limits are for each browser, both per-domain and max. What are the limits for Chrome, Firefox, Safari, Edge and IE 11?