The site itself is no longer maintained and updated to reflect changes to standards.
The first Acid test was a relatively simple test that could visually demonstrate if browsers implemented CSS. When IE became the dominant browser, Microsoft essentially stopped all development on IE. At the time, IE had a very broken implementation of CSS (although, it should be noted, IE6 was the best implementation of CSS when it came out, as everybody else was just as bad). The Acid2 test was created in large measure specifically to goad IE into improving its standard compliance (mostly on CSS). As a result of the publicity of the Acid2 test, the other browsers fixed their engines to pass Acid2, which put pressure on IE to fix their engine.
Since it had been effective in pushing browsers to implement the CSS2 standard correctly, the author turned to creating Acid3 to push browsers to implement more technologies. Whereas Acid1 and Acid2 were largely about CSS layout, Acid3 focuses more on testing JS API implementations. Acid3 was heavily criticized for letting browsers score well just by having a very thin, minimal surface implementation of the feature instead of testing thorough correctness, as well as for being very opinionated in pushing browsers to implement specific technologies (SVG fonts being the big one).
By the time Acid3 came out, there was already a change in the development of web browsers. Microsoft was once again participating in the standards compliance process and trying to drive their browser to modern compliance, so all of the major browser vendors were very active in discussion about implementation. Also, the W3C changed its specification process to rely more heavily on having a thorough compliance testsuite that had two passing independent implementations before a standard could be considered finalized. The CSS2.1 testsuite wasn't complete at the time these tests were developed, but has now come out, with almost 10,000 individual tests in them, far more thorough than any of the Acid tests could claim to be.
Since the Acid tests no longer had value in being the most comprehensive tests of their underlying functionality, nor in compelling browser developers to be competitive in standards support, their developer stopped working on the project. Indeed, since Acid3 fails at even being a comprehensive test for what it tests, its author publicly stated that he isn't interested in updating it when specifications update.
IE gets 100/100 ... while firefox got 97. That explains it!
It doesn't surprise me, after seeing all the other stuff that happens in the web community...
Chromium 71: 97%, blocks 2&3 silver, pauses at 24, 64.
Firefox Quantum 64: 97%, blocks 2&3 silver, pauses at 24, 64, 65.
Bucket 2: DOM2 Core and DOM Events
Bucket 3: DOM2 Views, DOM 2 Style, CSS3 selectors and Media Queries
By April 2017, the updated specifications had diverged from the test such that the latest versions of Google Chrome and Mozilla Firefox no longer pass the test as written. Hickson acknowledges that some aspects of the test were controversial and has written that the test "no longer reflects the consensus of the Web standards it purports to test, especially when it comes to issues affecting mobile browsers."
> Initially, Firefox 4 scored 97/100, because it did not support SVG fonts. Later, Firefox 4 scored 100/100, because the SVG font tests were removed from Acid3.
> According to Mozilla employee Robert O'Callahan, Firefox did not support SVG fonts because Mozilla considered WOFF a superior alternative to SVG fonts. Another Mozilla engineer, Boris Zbarsky, claimed that the subset of the specification implemented in Webkit and Opera gives no benefits to web authors or users over WOFF, and he asserted that implementing SVG Fonts fully in a web browser is hard because it was "not designed with integration with HTML in mind".
What does it mean by "71 pass"?
After checking in other browsers I edited the title but missed the 71. Fixed! TGIF
--2019-01-18 13:46:40-- http://acid3.acidtests.org/support-a.png
Resolving acid3.acidtests.org (acid3.acidtests.org)... 126.96.36.199
Connecting to acid3.acidtests.org
HTTP request sent, awaiting response... 404 Not Found
2019-01-18 13:46:40 ERROR 404: Not Found.
It's actually sending a PNG file, but with a 404 response.
The Acid3 test on that website is officially unmaintained: https://lists.w3.org/Archives/Public/www-archive/2017Jul/000...
E.g. on my phone (iPhone, up-to-dare, I think) which scored 98/100 I get:
Failed 2 tests.
Test 23 failed: expected '14' but got '5' - wrong exception for createElementNS('null', ':div')
Test 25 failed: wrong exception
Total elapsed time: 0.49s
The first one means it passed invalid parameters to createElementNS and expected a NamespaceError (14) exception but an InvalidCharacterError (5) exception occurred instead.
(I’m waiting at the drs office, and am happy to pass the time looking up error codes.)
Browsers aim to be backwards compatible with popular or influential sites, not synthetic tests.
So I figure it's one of three things going on here. One, modern browser makers just don't bother testing Acid3 anymore, and bugs have crept into the browser. Two, modern browsers knowingly break Acid3 because they prefer to implement performance enhancements that are not strictly compliant with standards. Three, updated standards have added syntax or rules that invalidate some of the strange stuff that is packed into Acid3.
See, for one example: http://www.howtocreate.co.uk/SGMLComments.html#simple
Someone remembers XHTML..?