Wednesday, June 11th, 2008
The IE team has created a new value for the X-UA-Compatible header in IE 8 IE=EmulateIE7.
We already had IE=7, which causes the page to be displayed in “IE7 Standards mode.” This forces both quirks and standards mode pages up that path, and people were asking for a solution that only pushes the non-quirks mode ones to change, thus the new option:
In response to the great IE8 Beta 1 feedback weâ€™ve received so far, we are introducing the â€œIE=EmulateIE7â€ tag to address this problem. EmulateIE7 tells IE8 to display standards DOCTYPEs in IE7 Standards mode, and Quirks DOCTYPEs in Quirks mode. We believe this will be the preferred IE7 compatibility mode for most cases. Support for IE=EmulateIE7 is available now as part of the IE June Security Update for IE8 Beta 1. Installing this update will enable you to verify youâ€™ve applied the EmulateIE7 tag to your site correctly.
Implementing the HTTP header is beneficial if a site owner wants most of their site to render as it did in IE7 or if there are no plans to update site content. Inclusion of this header honors any Quirks mode pages that belong to the site.
Using the meta-tag on a per-page basis is beneficial when the publisher wants to opt-in specific pages to render as they did in IE7.
The X-UA-Compatible tag and header override any existing DOCTYPE. Also, the mode specified by the page takes precedent over the HTTP header. For example, you could add the EmulateIE7 HTTP header to a site, and set specific pages to display in IE8 mode (by using the meta-tag with content=â€IE8â€).
Using the IE=EmulateIE7 compatibility tag is a simple way for users to continue their current experience when browsing your site until you can update with more standards-compliant content. Although adding this tag will prevent most display issues, you may also need to update your site to properly detect IE8. To learn more about IE8 document compatibility and browser detection, check out the IE Compatibility Center.
Posted by Dion Almaer at 7:22 am