Can I tell what browser version the user is using?

Certain features, like "glow" do not work in browser 1.19 and earlier. It seems to require 1.20 or later. Is there a way for a script to determine what browser is being used so that I can either offer a feature, or not, depending upon which browser the user is using at the moment?
Just detecting the version number would work fine for me.
Thanks.

Not automatically, but you could do something like offer a dialog asking the user whether they are using (official viewer) 1.20 or later, or whether their viewer (maybe it isn't an official viewer) supports prim glow.

Thanks, Hewee. I really want an automatic way - since many folk don't know what browser they are running, or even how to find out. I will wait until the mandated browser includes GLOW_PRIM.