Update 2008-01-23: See the followup on QA.
I have discussed a lot in the past about possible versioning mechanisms. A ‘meta’ element and http headers were two of the possibilities I had mentioned. Today, Chris Wilson (Microsoft and chair of the HTML WG) has announced in compatibility and IE8 that Microsoft worked with the WASP to propose an opt-in versioning mechanism.
The summary is
- “Quirks mode” remains the same, and compatible with current content.
- “Standards mode” remains the same as IE7, and compatible with current content.
- If you (the page developer) really want the best standards support IE8 can give, you can get it by inserting a simple <meta> element. Aaron gives more details on this in his article.
In the WASP article, it is explained as
<meta http-equiv="X-UA-Compatible" content="IE=8" />
My question to Chris Wilson:
Does IE8 support this opt-in mechanism when sent as an HTTP header only, without the meta in the document?
GET / HTTP/1.1 Host: www.example.org X-UA-Compatible: IE=8
Update: Answers in the comments suggest that it doesn’t respect HTTP protocol.