Re: Cross-Origin Resources and Resource Timing

Hi people,

I fully agree with Bryan McQuade on this one: make it opt-in for HTTP,
opt-out for HTTPS.
If it is opt-out for HTTP, I expect *very* little adoption from third party
providers.

In the past years, only a few third parties have improved their
widget/tracker/ad code for better performance.
Per today, most providers still give site owners crappy code
(document.write, global JS variables, etc etc) and latency can be very high.

There is very little to no incentive for them to start sending that
Timing-Allow-Origin: * header.

As a web perf optimization consultant, I have seen third party scripts
significantly impacting page load times and user experience on numerous
occasions. Real User Monitoring services need to be able to capture the
detail timing info so site owners get the full insight.

Please, please, please change the spec, to enable site owners to better
understand the performance of third party resources.

- Aaron Peters