By default, Internet Explorer 8 displays standards-based Web sites as closely to industry standards as possible. Certain Web sites do not display properly when viewed in Internet Explorer 8 Standards mode. To try to display such sites correctly, users can enable Compatibility View.

There are three ways to enable Compatibility View.

• Clicking the Compatibility View button in the Address bar. When displayed, this button appears to the left of the Refresh button and contains an image of a broken piece of paper. This enables Compatibility mode for all documents in the domain of the Web site being viewed.
• Enabling the "Display all websites in Compatibility Mode setting" in the Compatibility View Settings.
• Enabling the Compatibility View List, which defines a list of Web sites that are automatically displayed in Compatibility View.

This article describes the Compatibility View List, also known as the Compatibility List. It explains how the Compatibility View List was created, how to determine if your site is in the list, and how to have your site removed from the list.

Introducing the Compatibility View List

Internet Explorer 8 contains a new display mode called Internet Explorer 8 Standards mode that is more aligned to industry standards, such as the Cascading Style Sheets, Level 2.1 (CSS2.1)  from World Wide Web Consortium .

Web authors use doctype directives to specify whether their pages should be displayed in standards mode or a compatibility mode called "quirks mode." Internet Explorer 8 provides a new standards mode that supports industry standards more completely than the standards modes of earlier versions. By default, Internet Explorer 8 uses Internet Explorer 8 Standards mode to display standards mode Web pages. For pages built to support the features of earlier versions of the browser, this can affect what the user sees when the page is displayed. Pages that displayed properly in Internet Explorer 7 standards mode may appear differently when displayed in Internet Explorer 8 standards mode.

To overcome potential compatibility issues, the Compatibility View button allows users to display troublesome pages in Internet Explorer 7 standards mode. During the development of Internet Explorer 8, users took advantage of the Compatibility View button, and those choices created telemetry data that was later used to generate a list of Web sites that were better when viewed in Compatibility mode.

For the final release of Internet Explorer 8, this user feedback was combined with information listing the most highly visited Web sites per region. This created the Compatibility View List, which automatically displays Web sites in Compatibility View without further interaction.

The choice to view sites in Compatibility View is always up to the user and can be changed at any time. Users enable Compatibility View updates when Internet Explorer 8 is installed. The Compatibility List can be disabled through the Compatibility View Settings.

The Compatibility List also provides Web developers with additional time to support features in Internet Explorer 8. It will take time to update Web sites to integrate the improved standards support available with Internet Explorer 8 standards mode. The Compatibility List is a short-term solution intended to bridge this transition and make it easier for end users to enjoy the Web browing experience.

For more information, see Internet Explorer Blog: Compatibility View Recap .

Understanding 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 that the X-UA-COMPATIBLE header has greater precedence than Compatibility View. If a Web site is on the Compatibility View List and a page on that site includes 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. For more information, see Defining Document Compatibility.

How the Compatibility View List was Created

The Compatibility View List is based on feedback collected during the development of Internet Explorer 8. Several sources were used.

• Users of pre-release versions were given the option to provide information when they clicked the Compatibility Viewbutton. This information does not personally identify the user and was only obtained with the user's consent, in accordance with the Internet Explorer 8 Privacy Policy.

• The Report a Web Page Add-on allowed users to report incompatibility problems as they were encountered.

• Additional feedback submitted through forums, comments, and other sources of community feedback.

This information was objectively reviewed and collated into a list of the most frequently visited sites, by region.

When Internet Explorer 8 is first installed, the Compatibility View List is empty. If you choose to install updates during the installation process, the latest version of the Compatibility List is installed at that time. If the "Include updated website lists from Microsoft" setting is selected in the Compatibility View Settings, updates to the Compatibility View List are provided through Windows Update on a regular basis.

To disable the Compatibility View List at any time, use the Compatibility View Settings to disable the "Include updated website lists from Microsoft" setting. Additional settings allow you to further customize the Compatibility View Settings.

Determining if Your Site is in the Compatibility View List

You can download an Excel spreadsheet containing the current Compatibility List from the Download Center. The spreadsheet tracks when sites were added to the list and their removal status, if applicable. The Compatibility List is updated on a regular basis.

If you've installed and enabled the Compatibility View List, you can view the list in XML format by typing the following in the Internet Explorer 8 Address bar.

res://iecompat.dll/iecompatdata.xml

Removing Your Site from the Compatibility View List

To remove your site from the Compatibility View List, start by ensuring that your site displays accurately in Internet Explorer 8 Standards mode. Use the Developer Tools to change the Browser Mode to Internet Explorer 8 and verify that your site works as expected.

The following tips can help you isolate and understand problems that prevent your sites from working effectively in Internet Explorer 8 Standards mode.

• For best results during this process, make sure your pages do not include any X-UA-COMPATIBLE headers and that Compatibility View is disabled, as described earlier.

• The Developer Tools let you display your Web pages in different rendering modes; they also help you understand the relationship between the markup in the source of a Web page and the way the page is displayed. As a result, the Developer Tools are particular useful for isolating markup issues.

  Press F12 or select Developer Tools from the Tools menu to activate the Developer Tools. For more information, see Testing Browser and Document Compatibility Modes with the Developer Tools.

• If the Compatibility View button appears when you display your Web page, you are viewing the page in Internet Explorer 8 Standards mode. However, the reverse is not true. Several environmental factors can hide the Compatability View button; for more information, see Defining Document Compatibility.

Alternatively, you can use X-UA-COMPATIBLE headers to tell Internet Explorer 8 to use Internet Explorer 7 Standards mode to render your standards-based Web pages. For more information, see Defining Document Compatibility. (This is recommended as a temporary measure while the underlying issues are investigated and resolved.)

To remove your site from the Compatibility View List (or to dispute the removal of your site from the list), have the overall site owner send an e-mail to iepo@microsoft.com that contains the following information.

• Owner Name
• Corporate Title
• Company Name
• Street Address
• Email Address
• Telephone Number
• Web site Address

Microsoft will review the provided information and remove your site from the Compatibility View List at the next scheduled list update. The supplied information will only be used for the purposes described here and will not be shared with any third party.