[davidmurdoch]

My totally unmeasured hunch is that there is a downside to using noopener: it could make the new page that is being opened take slightly longer, since it now needs to spool up another process/thread/sandbox/whatever instead of piggy backing off the existing page's.

More about the performance "benefit" here: https://jakearchibald.com/2016/performance-benefits-of-rel-n...

[anewhnaccount2]

That page says the opposite of what you just said.

[davidmurdoch]

For an origin page utilizing 100% of it's available processor resources, yes.

But in the real world most websites don't do this. What likely matters to the user is that the page they're navigating to opens faster; the user likely doesn't care about the performance of the hidden tab they just came from.

Of course, `noopener` has security and privacy benefits which may outweigh the performance costs (if there are any).

[mbell]

I think this is largely a non-issue now due to spectre mitigations. e.g. Chrome is enabling site-isolation by default which would run the new page in a separate process anyway. I think the other major browsers are also doing something similar.