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I just saw this meta tag in the wild and was wondering it does and why it's used?

<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />

Reading the documentation on About.com, it says:

"IE=edge" tells Internet Explorer to use the highest mode available to that version of IE. Internet Explorer 8 can support up to IE8 modes, IE9 can support IE9 modes and so on.

But what about the chrome=1 tag?

Stefan Steiger
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sergserg
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2 Answers2

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It's for Google's Chrome Frame browser add-on.

ChromeFrame can be installed on various versions of IE (especially handy for older versions that don't play nicely with modern web features). It essentially runs the chrome browser inside of IE.

In the case of the meta tag, IE should run in standards mode (most current edition "Edge") - and activate chrome frames if it exists.

I usually do some conditional browser stuff for older versions of IE, allowing the user to install the add-on as an option.

More here : chrome frame API

(Keep in mind that Google Chrome Frame is no longer supported)

Micky McQuade
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Bosworth99
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    I'd like to point out that MSDN documentation also states that you should only use IE=edge in testing environments only. – Robbiegod May 29 '13 at 18:01
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    and that Chrome Frame [will be deprecated](http://www.google.com/chromeframe?prefersystemlevel=true) as of January 2014 – 0skar Aug 01 '13 at 08:08
  • Interesting. Hadn't read that. Well - its probably fine. It was a nice bandaid, though. – Bosworth99 Aug 01 '13 at 15:01
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    For info, chrome frame is now [discontinued](http://blog.chromium.org/2013/06/retiring-chrome-frame.html). This line may no longer be relevant for new projects. – Offirmo Jul 18 '14 at 08:34
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    Not sure if it was always this way or has changed since discontinuation of chrome frame, but "IE=edge,chrome=1" does not validate at w3c. Has to be "IE=edge". – Yardboy Dec 18 '14 at 16:54
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    "Starting with IE11, edge mode is considered the preferred document mode." - from https://msdn.microsoft.com/en-us/library/jj676915%28v=vs.85%29.aspx – Roy Tinker Mar 20 '15 at 22:40
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Also, starting in IE11 "edge" mode, which used to be experimental, is now the "preferred" mode - see Compatibility changes in IE11 Preview

Additionally, "document modes" are generally being deprecated in IE11 all together, so you should probably try to stop depending on them.

BenMorel
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Doug Rohrer
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