Wednesday, November 9, 2011

The Acid3 of JS has a few surprises.

Edit: Updated Results Are Available Here

Wikipedia has an article on a Javascript conformance test called sputnik from Google.

It has the results from various Desktop browsers on how standards-compliant they are. Now I know what you are thinking, probably #1 is Chrome because the test is from Google, followed by Opera, Safari, and Firefox; with IE trailing behind in a pitiful display of brokenness.

But that's not what Wikipedia shows. In fact, it shows IE as the most standards-compliant browser.

Microsoft has quite brilliant engineers and recently they've began to take their browser seriously again, but to say that Internet Explorer has the most standards compliant JS engine? This would be quite a departure from history.

I needed to verify these results, for my own sanity.

According to Wikipedia, the test has changed hands and is now hosted at You can go there now, it's on a domain registered by Mozilla Corporation. So this doesn't look like some wonky unfair comparison that almost looks to be designed to make Microsoft look good. Let's get questions of legitimacy out of the way.

Here's the updated (2011-11-09) results. Each browser's data is compressed with bzip2.
BrowserFailsThe photoThe data
IE 10 10.0.8102.06ScreenshotXML Results
Firefox 8.0164ScreenshotXML Results
Firefox 9.0 (2011-11-08)164ScreenshotXML Results
IE 9 9.0.8112.16421322ScreenshotXML Results
Chrome 16.0.912.32 beta-m415ScreenshotXML Results
Chrome 15.0.874.106 m416ScreenshotXML Results
Opera 11.523750ScreenshotXML Results
IE 8 8.0.6001.18702N/A[1]ScreenshotN/A
1The test fails to run in IE8 and hits a Javascript error fairly early on.

IE 10 did the best by far. Surprised? Me too. The next up was Firefox. Also surprised? Yeah, here too. Then IE 9 ... IE 9? The world is crazy sometimes. Chrome comes in right above Opera, which basically eats shit ... that's a new one. What has this world come to?

One of the important things to note is that failures seem to happen in batches. That is to say it's successful for a few hundred (or a few thousand) tests, then a bunch of tests fail consecutively. Almost makes me think of that math exam you once got where questions 2-8 depended on you getting question 1 right.

These tests also don't speak to how performant the browsers are on, well, anything. Their are more factors than compliance-to-standards when it comes to providing the best web experience. Regardless, these results certainly support the on-going notion that IE is finally back in the running.

Further Work

I just looked at the number of failed tests; not focusing on the content of what tests failed. I'm not familiar enough (and just plain not smart enough) with the internals of ECMAScript to know whether the results warrant further investigation or concern. I do know from my own experience that I've fallen victim to many more IE Javascript bugs then other browsers. And perhaps, that's the important thing; not whether a feature is implemented, or passes a smoke screen test, but whether the feature has problems. It would be great to hear what some of the browser developers have to say about these results.

Tests were done on Windows 8, XP, and Vista; to try to main consistency. If you want to contact the author, reply here below. The author is Chris McKenzie; a programmer dedicated to truth, no matter how crazy it gets. Check out his projects on github.


  1. Opera 11.60 Beta (final release probably will be within few days) "pass" the test with "only" 11 fails. Opera 12 probably will be even better.

  2. Opera 11.60 Beta results:

  3. Wonderful! Do you have the xml too, just to be formal?

  4. Also if you could put the build information in the screenshot like I do with mine, that would be perfect. Otherwise, I'll do it by saturday

  5. Firefox 10 nightlu also fails 164 tests.

  6. Opera 11.60 fails 11 tests — 10 of these are due to UA sniffing in the test harness (sth.js — modify that so Opera goes down the same code-path as everything else and you have a single failure).

  7. @gsnedders: Wow. If you think it's a bug, let's try to find the authors of that test and see if we can get them to address it. That's really good!