Internet Explorer program manager Markus Mielke acknowledged that Microsoft has a long road ahead in efforts to achieve CSS standards compliance, saying IE7 was only a "stepping stone." The company has made over 200 "behavior changes" for CSS 2.1, which it outlined Tuesday.

IE7 is currently being locked down and is expected to be completed later this year. The new browser has largely been layout-complete since March, with minor tweaks and interface improvements coming in Beta 2 and Beta 3 this summer.

Mielke notes that Microsoft listened to feedback and prioritized fixes and features for IE7, in addition to partnering with the Web Standards Project. "We understand that we are far from being done and we know we have still a lot of work ahead of us," he said.

"As an example, in the platform we did not focus on any proprietary properties – though we may try out new features in the future using the official –ms- prefix, following the CSS extension mechanism," Mielke added.

Still, the slew of CSS bug fixes may not encourage developers to fix their sites or herald the end to CSS hacks, even once IE7 reaches broad adoption. The changes only take affect when a DOCTYPE is set on the Web site. "To preserve application compatibility we will not make any behavioral changes to “quirks mode” as it has been established since IE6," Mielke said.

"As we struggle to balance the needs of our user customers with the desires of web developers, we need your help. The only way for us to continue to improve our standards support is to get your help in changing your sites for IE7."

Microsoft is providing a set of documentation and tools that developers can use to prepare for IE7, which will also be the default browser in Windows Vista. "We are already planning for the next IE release and will continue down the road of improving our CSS support," Mielke added.