[JshWright]

What don't you buy? They test with a certain set of supported platforms. If a client isn't one of those (whitelisted) platforms, then they may send out a bunch of inefficient polyfills so they know XYZ functionality exists, even if it's slow.

[jacquesm]

Except that it works just fine if those 'unsupported' platforms are treated in the exact same way as the supported ones. To make it seem as if a whole pile of work was done in order to make unsupported platforms work less well but this is a good thing is something that I find very hard to reconcile. And if this were a company that did not have a history of exactly such tricks it might be more believable, MS - with me at least - does definitely not have the benefit of the doubt in cases like these.

[JshWright]

No, a whole bunch of work was (hypothetically) _not_ done to verify if they were supported or not. I'm not suggesting that it's a good thing, I'm suggesting that laziness, sloppiness, or a simple oversight are just as plausible as malice.

It is _less_ effort to say "We support these specific platforms, and rather than doing actual feature detection, we'll just load a bunch of polyfills to make it work on anything else".

[emodendroket]

How thoroughly do you figure that guy posting the question tested it compared to whatever QA process MS does for supported platforms?

[jacquesm]

Good enough to detect a problem.

[emodendroket]

lol.