{mosimage}In its browser blog, Microsoft acknowledged that IE 7 would not pass the Web Standards Project's Acid2 test, which examines a browser's support for W3C (World Wide Web Consortium) recommendations including CSS1 (Cascading Style Sheets), HTML4 and PNG (Portable Network Graphics).

"We will not pass this test when IE7 ships," Chris Wilson, lead program manager for the Web platform in IE, wrote in the IE blog. "We fully recognize that IE is behind the game today in CSS support. We've dug through the Acid2 test and analyzed IE's problems with the test in some great detail, and we've made sure the bugs and features are on our list--however, there are some fairly large and difficult features to implement, and they will not all sort to the top of the stack in IE7."

Opera was "very close" to passing Acid2 whilst, Apple has already said that its Safari browser passes the test in preliminary builds. The Mozilla Foundation said it was committed to "full support" of Acid2 in its Firefox browser but did not say when it expected to pass the test.