Understanding IE8 Compatibility View

Before displaying a standards-mode web page, Internet Explorer 8 checks to see if the Domain Name of the Web site appears in the Compatibility View list. if so, the site is displayed using Compatibility View. if not, and the page contains no other direction, Internet Explorer 8 displays the page in Internet Explorer 8 standards mode.

 

When a standards-based web page is displayed in Compatibility View, the following changes occur.
•Pages are displayed in IE7 mode rather than IE8 mode.
•In the User-Agent string, the browser identifies itself as MSIE 7.0 instead of MSIE 8.0.
•Conditional comments and Version Vectors recognize the browser as Internet Explorer 7, rather than Internet Explorer 8.

These changes help ensure that users can still use web sites that do not fully support the features of Internet Explorer 8.

 

Please note thatX-UA-COMPATIBLE HeaderHas greater precedence than Compatibility View.If a web site is on the Compatibility View list and a page on that site has des an X-UA-COMPATIBLE header telling Internet Explorer 8 to display a page in IE8 mode, the page is displayed in Internet Explorer 8 standards mode. this allows web developers to support Internet Explorer 8 standards mode on an incremental basis.