Standards Conformance
Composite Scoring
The standards conformance composite is determined by dividing the results of each test by the maximum score of that test, then multiplying by 100 to get a percentage. The percentage results of the three tests are then averaged together to achieve a composite grade.
Chrome takes first place on both operating systems with a B-. It is followed by Safari in second place on OS X with Opera and Firefox caught up in a tie for last, both achieving an equal C. Opera manages an extra percentage point on Windows 7 to place second with Firefox close behind in third. Last place in Windows 7 goes to Microsoft's own IE9 with the only failing grade.
Drill Down
The charts below are for the three standards conformance tests: Ecmascript Language test262, HTML5Test.com, and The CSS3 Test.
IE9 is significantly behind the curve in all three disciplines, while Chrome's better-than-average HTML5 and CSS3 scores allow Google to dominate standards conformance.
(The nice popular ones like ABP, Lazarus, Greasemonkey all have equivalents; some lesser-used plugins like Rikaichan also have ports by now. Only a matter of time!)
as always, a great read.
Testing these browsers at stock doesn't reveal even an eighth of the picture.