<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /> Does it really render page like IE7 in IE8?

Question

Will i get same result in IE7 and IE8 after using this <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /> ?

Has anyone tested it?

Answer 1

The X-UA-Compatible header, at least in IE8, triggers IE8's IE7 mode. You can simulate the same effect using the developer toolbar in the browser. It is not a perfect emulation of IE7. There are some bugs in the implementation.

According to Microsoft's explanation of the header, it should behave exactly like IE7 when given this header, however at least for this version of Internet Explorer, it is broken just enough that you shouldn't trust it completely.

If your site works in IE7 already and doesn't work in IE8, using IE7 emulation mode may keep you safe for this release of IE. If it doesn't work for you, fixing your site to work in IE7 mode might be faster than truly fixing it for IE8. This assumes you have no other browsers to develop for.

I don't have any tests readily available unfortunately.