"X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE"

Kuttan Sujith picture Kuttan Sujith · Jan 30, 2013 · Viewed 389.7k times · Source
<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE" />
  1. Actually what is the meaning of this statement ?

  2. Some of the examples use , to separate versions of IE, while some use ;; which is correct?

  3. The order IE=9; IE=8; IE=7; IE=EDGE has some importance, I wish to know that.

Edit: I am using <!DOCTYPE html>

Answer

PlantTheIdea picture PlantTheIdea · Jan 30, 2013

If you support IE, for versions of Internet Explorer 8 and above, this:

<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7" />

Forces the browser to render as that particular version's standards. It is not supported for IE7 and below.

If you separate with semi-colon, it sets compatibility levels for different versions. For example:

<meta http-equiv="X-UA-Compatible" content="IE=7; IE=9" />

Renders IE7 and IE8 as IE7, but IE9 as IE9. It allows for different levels of backwards compatibility. In real life, though, you should only chose one of the options:

<meta http-equiv="X-UA-Compatible" content="IE=8" />

This allows for much easier testing and maintenance. Although generally the more useful version of this is using Emulate:

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />

For this:

<meta http-equiv="X-UA-Compatible" content="IE=Edge" />

It forces the browser the render at whatever the most recent version's standards are.

For more information, there is plenty to read about on MSDN,