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Microsoft introduces an HTTP header that makes IE8 switch from standards compliant mode (the default) into IE7 mode (which is less standards-aware):
X-UA-Compatible: IE=EmulateIE7
There also is an http-equivalent meta tag:
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7">
If you're unable to test your sites in IE8, it may be a good idea to add the header to your webserver config - just to be on the safe side.
Earlier thread: [webmasterworld.com...]
The original document on MSDN (cc288325(V.85).aspx - "Defining Document Compatibility") did not have this information - I know for sure because I printed it out.
I'm annoyed because the few sentences added that explain about using the content atribute "IE=emulateIE7" were not included when the Beta was released and, clearly, it should have been.
In another thread on this site I wrote something which I have now found out is wrong:
Before testing, make sure you've got it straight exactly how the versioning metatag works.
In IE8, doctype switching means nothing. There is no doctype switching. All the mode switching is done with the metatag.IE behaving as #8
<meta http-equiv="X-UA-Compatible" content="IE=8" />
OR
you may still force it to behave as #7
<meta http-equiv="X-UA-Compatible" content="IE=7" />I want to add that quirks mode is triggered by:
<meta http-equiv="X-UA-Compatible" content="IE=5" />
Now, as it turns out, there is "emulateIE7" which, I ASSUME will cause IE8 to emulate IE7 in standards mode or IE7 in quirks mode, depending upon the doctype!
Assuming this is correct, and remains Microsoft's final word on the subject, I have to assume that:
1) content="IE=emulateIE7" with a standards triggering doctype acts the same as content="IE=7"
2) content="emulateIE7" with a quirks triggering doctype (or no doctype at all) acts the same as content="IE=5"
@anyone who has been keeping track of this IE8 versioning thing:
Do you agree? Does this pretty well sum it up?
