Internet Explorer 10 Turning Compatibility mode on (From server)

In order to turn Compatibility mode on for Internet Explorer the server should send “X-UA-Compatible” as a header with the value IE=EmulateIE9. This will force Internet explorer to use compatibility mode if it is a version higher than 9

If we using ISS (making for instance a asp.net project) the following web.config can be used to do this.

<configuration>
  <!-- Other settings -->
  <system.webServer>
    <httpProtocol>
      <customHeaders>
        <clear />
        <add name="X-UA-Compatible" value="IE=EmulateIE9" />
      </customHeaders>
    </httpProtocol>
  </system.webServer>
</configuration>

Mode details on the possible values for the header tag

Sometimes sending this as a header tag works, then this should be sent first in the header tag

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE9" />

Internet Explorer 10 Turning Compatibility mode off (From server)

In order to turn Compatibility mode off for Internet Explorer the server should send “X-UA-Compatible” as a header with the value IE=Edge. This will force Internet explorer to use the latest mode the version has (this works from IE 6 to 11 and up)

If we using ISS (making for instance a asp.net project) the following web.config can be used to do this.

<configuration>
  <!-- Other settings -->
  <system.webServer>
    <httpProtocol>
      <customHeaders>
        <clear />
        <add name="X-UA-Compatible" value="IE=Edge" />
      </customHeaders>
    </httpProtocol>
  </system.webServer>
</configuration>

Mode details on the possible values for the header tag