Microsoft says IE9 is "the world's fastest browser." Mozilla claims IE9 doesn't even qualify as modern.
As Mozilla's Firefox 4 and Internet Explorer 9 move closer to release, the browser makers are sparring over each other's HTML5 capabilities, lobbing insults and contradictory test results.
After Microsoft claimed IE9 achieves 99% compliance with HTML5, compared to Firefox's 50%, Mozilla Corp. technology "evangelist" Paul Rouget fired back with a blog post titled "Is IE9 a modern browser? NO."
The HTML5 standard won't be finished until 2014, so the posturing at this point is mostly for public relations. The World Wide Web Consortium has said it's too early to draw broad conclusions from HTML5 tests, but that's exactly what browser makers are doing.
Microsoft said it has submitted nearly 4,000 HTML5 tests to standards bodies, and that users can try the tests themselves - but only on an official Microsoft Web site.
Microsoft, which is also fighting a standards battle with Google over the codecs to be used in HTML5 videos, said this month that it has "the world's fastest browser." But Rouget begs to differ, saying it's no wonder Microsoft's own tests show IE9 knocking HTML5 out of the park.
"Does IE9 support 99% of the HTML5 specification as insinuated by Microsoft? No, they're actually pretty far from it," Rouget writes. "The tests Microsoft are referring to are the ones they created during the development of IE9. It's not that surprising that they pass the very tests they used to design and develop the browser - we score pretty well against our own unit-tests as well. The primary use case for these tests, however, is to spot regressions and validate code changes. In other words: the tests ensure that future changes don't break the things you just built. They don't actually test all elements of a specific standard."
Rouget pointed to a "real world test" on the site Caniuse.com, which he said shows Firefox 4 achieving 84% compatibility with all Web standards, compared to 61% for IE9. He also pointed to HTML5test.com, which has Firefox 4 achieving a score of 255 to IE9's 130.
Those scores are based on development and beta versions. For stable browser versions (IE8 and Firefox 3.6.8), Microsoft scores just 32 and Firefox just 156.
Google's Chrome, meanwhile, receives an HTML5 score of 283 for its stable version and 293 for the beta version, besting all desktop and mobile browsers.
But still another test puts IE9 in the lead. Former Linden Lab CTO Cory Ondrejka, now at Facebook, tested how HTML5 could apply to Web-based games, and posted results showing IE9 outstripping Chrome, with Firefox, Opera and Apple's Safari well behind.