Force IE compatibility mode off using tags

After many hours troubleshooting this stuff... Here are some quick highlights that helped us from the X-UA-Compatible docs: http://msdn.microsoft.com/en-us/library/cc288325(VS.85).aspx#ctl00_contentContainer_ctl16

Using <meta http-equiv="X-UA-Compatible" content=" _______ " />

  • The Standard User Agent modes (the non-emulate ones) ignore <!DOCTYPE> directives in your page and render based on the standards supported by that version of IE (e.g., IE=8 will better obey table border spacing and some pseudo selectors than IE=7).

  • Whereas, the Emulate modes tell IE to follow any <!DOCTYPE> directives in your page, rendering standards mode based the version you choose and quirks mode based on IE=5

  • Possible values for the content attribute are:

    content="IE=5"

    content="IE=7"

    content="IE=EmulateIE7"

    content="IE=8"

    content="IE=EmulateIE8"

    content="IE=9"

    content="IE=EmulateIE9"

    content="IE=edge"


There is the "edge" mode.

<html>
   <head>
      <meta http-equiv="X-UA-Compatible" content="IE=edge" />
      <title>My Web Page</title>
   </head>
   <body>
      <p>Content goes here.</p>
   </body>
</html>

From the linked MSDN page:

Edge mode tells Windows Internet Explorer to display content in the highest mode available, which actually breaks the “lock-in” paradigm. With Internet Explorer 8, this is equivalent to IE8 mode. If a (hypothetical) future release of Internet Explorer supported a higher compatibility mode, pages set to Edge mode would appear in the highest mode supported by that version; however, those same pages would still appear in IE8 mode when viewed with Internet Explorer 8.

However, "edge" mode is not encouraged in production use:

It is recommended that Web developers restrict their use of Edge mode to test pages and other non-production uses because of the possible unexpected results of rendering page content in future versions of Windows Internet Explorer.

I honestly don't entirely understand why. But according to this, the best way to go at the moment is using IE=8.