IE Enterprise Mode in a Nutshell

Note:  This document is based on the March 2015 and April 2015 versions of Enterprise Mode.

Overview

  • Compatibility mode introduced in IE11 in 2014.
  • Has priority over Compatibility View List and X-UA-Compatible meta tag.
  • Controlled through GPO and/or registry.

Priority

  • Can be configured through the following keys - priority from top to bottom:
    1. HKLM\SOFTWARE\Policies\Microsoft\Internet Explorer\Main\EnterpriseMode
    2. HKCU\Software\Policies\Microsoft\Internet Explorer\Main\EnterpriseMode
    3. HKCU\Software\Microsoft\Internet Explorer\Main\EnterpriseMode
    4. HKLM\SOFTWARE\Microsoft\Internet Explorer\Main\EnterpriseMode
  • Higher priority wins.
  • Configuration files are not merged.

Enable

  • Add one of these two registry keys:
  • Enabling allows access to the menu option Tools --> Enterprise Mode.
  • Setting the value to a URL enables logging.

Logging

  • Can centrally log when users turn EM on or off manually and for which web sites.
  • Sample ASP logging site EmFeedback.aspx

<%
    Response.AppendToLog("EMIEAutoFeedback:" + Request.Form["URL"] + "=" + Request.Form["EnterpriseMode"]);
%>

  • Adding prefix "EMIEAutoFeedback" allows for easier sorting and filtering.
  • Sample output:

2014-04-16 09:20:12 ::1 POST /EmFeedback.aspx
EMIEAutoFeedback:https://www.bing.com/=On
50144 - ::1 Mozilla/5.0+(Windows+NT+6.3;+WOW64;+Trident/7.0;+rv:11.0)+like+Gecko - 200 0 0 60

  • Locate IIS log file here: %SystemDrive%\inetpub\logs\LogFiles\
  • Locate IIS Express log file here: %USERPROFILE%\Documents\IISExpress\Logs\

Site list

CurrentVersion

  • After modifying the site list, change the version number in the file.
  • Restart Internet Explorer and wait for 65 seconds.
  • Check this registry key: HKCU\Software\Microsoft\Internet Explorer\Main\EnterpriseMode
  • It should contain a key called CurrentVersion with the same value as the version of the modified site list file.
  • This confirms that the file has been loaded and parsed correctly.

Document Mode (DocMode)

  • Like using X-UA-Compatible meta tag.
  • Overrides X-UA-Compatible meta tag.
  • EM7/8 offers higher fidelity emulation than DocMode 7/8. EM7 mode can be used to eliminate CV list.

Behavior of EM modes

 

  • Fallback to quirks if no DOCTYPE.
  • Sends UA-string for selected document mode.
  • Only "Default" and "Enterprise Mode" honor Compat View List and X-UA-Compatibility meta tag.
  • X-UA-Compatibility meta tag has priority over Compat View List.
  • Iframes inherit document mode (e.g. IE9, IE10, etc.) from parent, but can be in standard (edge) or quirks mode regardless of the parent itself being in either standard or quirks mode.
  • * F12 Developer Tools may display Edge or 10 document modes, respectively, even though the page is rendered in quirks mode.
  • EM7 mode is equivalent to EM8 mode + Compatibility View settings.

X-UA-Compatible

  • * F12 Developer Tools may display Edge or 10 document modes, respectively, even though the page is rendered in quirks mode.

Compatibility View List