I notice that yet another "benchmark" blog post from Microsoft is making the rounds on the internet.
As one might expect, the impression people are getting when reading the blog is not one that matches reality. The results are misleading unless you read the "fine print", which seems to escape most people who comment on it. You see, while the IE10 preview appears to come out on top, the results are not what most people think they are. …
A high score does not show overall compliance. It only shows whether you pass the currently available tests or not. This is a flashback to Microsoft's blog post on HTML5 compliance last year.
Here's what the actual test suite page says (emphasis mine):
- The test suite is not complete
- It is in active development
- It does not cover all parts of the specification
- There may be invalid tests
- Tests may yield false positive or false negative results
- A perfect score does not imply a perfect ES5 implementation
- Tests are being added and removed all the time
If you read the Microsoft blog post carefully, they do mention that it is a work in progress. But the way it is being reported on it's obvious that the message people read was "IE10 is the most compliant". The blog post also reveals that Microsoft submitted thousands of tests (which they should receive praise for), so it does not seem to be coincidental that they are reporting on it now.
In other words: While Microsoft briefly mentions in "fine print" that the test is not complete, it seems that most people are misled, and think the tests results say something that they don't.