For what it's worth, this could be used as a base for a polyfill, which would support pretty much everything IE11 or newer.
https://github.com/tracker1/node-uuid4/
"It is important to note that it still might not generate a unique value though the probability of that happening is fairly low."
It depends on your definition of "fairly". I would rather call:
"the number of random version-4 UUIDs which need to be generated in order to have a 50% probability of at least one collision is 2.71 quintillion ... This number is equivalent to generating 1 billion UUIDs per second for about 85 years. " extremely low ;-)
https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_(random)