[beaconstudios]

this is why I say it would have to be opt-in through something like a header or tag on the page in question (although I don't think doctype would work well for this). Existing sites would use the current engine and sites that explicitly stated they were for the new engine would be handled differently.

[manigandham]

That's exactly what IE did with the `X-UA-Compatible` meta tag. It's just more work for both browsers and websites to manage, which is why it's not used anymore.

https://msdn.microsoft.com/en-us/library/jj676915(v=vs.85).a...

[kijin]

Content-Security-Policy might be a good way to opt in to this kind of behavior.