As we have blogged about
times, one of our top goals for IE9 is enabling developers to utilize
enabling the same markup means changing existing Web platform behavior for standards-compliance
and interoperability. We have published and updated the list of changes to the platform
in the IE9 Guide for Developers
along with platform previews so that developers have an opportunity to try new features
and test early and often.
We carefully designed and implemented new platform features to ensure existing sites
continue to run well in IE9’s Standards mode. As a result, for many Web developers,
no additional work is required to prepare for IE9.
For sites that need to update, we have identified a set of changes more likely to
impact existing code that does not use
feature and behavior detection. These changes are documented in the
IE9 Compatibility Cookbook, which we will continue to update based on
your feedback. For your convenience, we have listed the changes with a higher probability
of impact below. Refer to the IE9 Compatibility Cookbook for in-depth information
on these changes.
Another important goal for IE9 is ensuring that legacy
document modes continue to behave the same as they did in previous versions
of IE. The only exceptions we make are to improve overall product quality in areas
such as security.
If you are updating your site from IE7 mode, you may also want to look at Tony’s
Site Compatibility and IE8 post.
If you think we’re missing a compatibility topic or one needs additional information,
please contribute through the
IE9 Compatibility Cookbook site.
—Tony Ross and Marc Silbey, Program Managers, Internet Explorer