Internet Explorer 8 gives users the choice about displaying a list of websites in “compatibility view.” This helps make websites that were created for older browsers, especially Internet Explorer 6 and 7, look better in IE 8 which renders web pages closer to the standards and thus differently from those versions of IE.
How Users Can Turn on Compatibility View
Anyone using Internet Explorer 8 can turn on compatibility view by clicking on the button to the left of the refresh button in the address bar (it looks like a broken piece of paper). They can also force all websites to be viewed in compatibility view by choosing that in the settings. Or they can choose to enable compatibility view automatically for sites on the compatibility view list that is regularly updated by Microsoft.
One place that IE always turns on compatibility view is when viewing web pages from a hard drive - not over the internet. This can be frustrating for designers who want to test their pages locally before uploading them to a hosting provider.
Also, if a web designer does not set a DOCTYPE, that will switch viewing of that page in IE to compatibility view. If you want to make sure your pages are viewed in standards view by Internet Explorer 8, you need to set a DOCTYPE on all your web pages.
Why is There a Compatibility View?
Microsoft created the compatibility view for Internet Explorer 8 to give web designers time to convert their pages over from the non-standard techniques used in IE 7 and IE 6, to a more web standard compliant version. It tells the browser to render the page as if it were IE version 7 rather than IE version 8.