Suff, I suspect the solution depends upon how often it happens and on which sites.
I know my graphics drivers are the latest as I keep them up to date via Intel.
With Opera the problem was the 'use hardware acceleration' which has been turned on by default for about the last six updates, so I manually turn it off. When it comes to WebGL in Opera
opera://flags shows that it is turned off with a warning that Enabling it could lead to browsing problems. The default is Disabled.
All the Chrome extension does is go into chrome://flags and disables WebGL without the danger of a novice user messing other things up. It is ever so tempting for some of us (Me) to wonder what might happen if I change this or that...!