In a report released Wednesday, Microsoft spelled out how it tests browsers in-house, and again stressed that it doesn't buy the idea that benchmarks -- such as those that score JavaScript performance -- accurately compare the players.
"These benchmarks necessarily characterize only a narrow set of the browser functions in a very constrained way," Microsoft's report said. "End users, however, do not operate in a controlled environment."
Microsoft did not test other browsers, such as Apple Inc.'s Safari or Opera Software ASA's Opera, said James Pratt, a senior product manager on the IE development team, because it wanted to focus on rivals that "had a good share on the Windows platform."
Both Opera and Safari for Windows have shares of less than 1%, according to the most recent data from Net Applications Inc., with the former, on all platforms, accounting for 0.7% and the latter just 0.3%.Nor did Microsoft put IE8 in the ring with later versions of Chrome and Firefox.
"IE8 RC1 is a release candidate, and was very close to being done," explained Pratt when asked why newer versions of Chrome and Firefox had not been used. "But Google and Mozilla were still actively working on [those newer browsers], and they weren't super stable."
Although Google did not respond to a request for comment on Microsoft's benchmarks, Mozilla's Mike Shaver, who heads all development at the company, applauded any attempt to boost IE's performance. "I don't think anyone here has had a chance to really look at their methodology yet or tried to reproduce their results, but to whatever extent Microsoft is working to improve the performance of IE, it's a good thing for the Web," said Shaver in an e-mail late Thursday.
