Take your Kindle and visit https://html5test.com/ and that should give you a good idea. Spoiler: it scores pretty low but supports JavaScript, which is surprising. PS: You could have gotten this answered more quickly by Googling. - Source: Hacker News / 8 months ago

I just don't know what else I can do. I compared Chromium and Firefox in html5test.com, got same result. All browsers says they doesn't support H.265. I turned off HW acceleration, nothing changes. I installed ffmpeg-libs and other codecs from Fedora wiki. Nothing changes. Videos are same vp9 in browsers. I spent all day googling but nothing helpful. Source: almost 2 years ago

What does https://html5test.com/ say for h.264, VP8, VP9 and Theora support? What does it say for aac, Opus, Vorbis and mp3 support? Source: almost 2 years ago

You can use this website also https://html5test.com is really helpful with more datails. Source: almost 2 years ago

If I go on html5test.com, no matter which browser I use, H265 support is not enabled and I couldn't find any article online that explains why -- what am I missing here? Source: almost 2 years ago

There’s websites decided to pointing out which standards various browsers do & don’t support. https://caniuse.com/ (And older not as relevant one is http://acid3.acidtests.org/ ). - Source: Hacker News / over 1 year ago

Https://shadow.goose.icu/?http://acid3.acidtests.org/. - Source: Hacker News / almost 2 years ago

During the browser wars, web developers created “Acid Tests” to see how well a browser supported various style sheet and markup conventions. When the acid tests became popular, there were accusations that browser engineers were manipulating their rendering engines to pass those tests. For instance, some cascading style sheet attribute would pass the test, but fail to work as expected under normal use on a web page. Source: over 2 years ago

I am sure that both firefox and chromium-based browsers will pass most of something like ACID3 test. But at this stage standards have nothing to do with reality. Standards define perhaps 10% of the code you are writing and interpretation of the rest 90% of the code is up to the browsers. Source: about 3 years ago

The old version (http://acid3.acidtests.org/) will reach 97/100 on modern compliant browsers. There is a newer version (https://wpt.live/acid/acid3/test.html) which incorporates the changes made to the specs in the meantime, so modern browsers will reach 100/100 on this one again. The test was carried out against this version, as you can see in the address bar in the screenshot. - Source: Hacker News / over 3 years ago