IE11: Compatibility List vs. X-UA-Compatible
Yesterday I published a topic in which I described some amazing decisions that Microsoft made when releasing new versions of its Internet Explorer browser. In short, these are:- the introduction of compatibility modes with all previously released versions of the browser up to 5.5;
- the decision to emulate this compatibility by carefully porting old bugs;
- Refusing to specify the browser name in the user agent against the background of claims that IE11 should not be detected by the user agent;
- scrapping backward compatibility between the latest Developer Preview and RTM release;
- different behavior, up to and including the fall in some situations, of the same browser under different versions of the operating system;
- maintaining a global compatibility list, which includes those sites that, according to Microsoft, should be shown in one of the IE compatibility modes;
- the formation of this list on the basis of statistics on user clicks of preview versions of the browser in the “Compatibility View” button;
- the priority of this list over the webmaster's specified X-UA-Compatible meta in RTM build IE11.
The appearance of this topic caused a wave of good-natured comments, ranging from “the author of the hysteric” (as if some of the facts described become less significant from this) to “So much nonsense, I have not read for a long time. It does not even make sense to go through the whole article and point out the author’s mistakes . ” To the request to indicate errors in the presentation, for some reason, it was only noted that the last of these points - namely, the priority of the compatibility list over X-UA-Compatible - does not correspond to reality (strangely, why then the “errors” in the plural, dear SowingSadness ?). Further, in a thread, they demanded that I provide evidence of this clause, stating that I either made a mistake or simply invented it.
Test assembly: Windows RT 8.1 on a Microsoft Surface. See the version and build of IE11 in the screenshot at the beginning of the post.
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HTML code on which the meta-tag was checked:
<!DOCTYPE html> <html> <head> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <title>Compat View Test</title> </head> <body> <h1>Hello, Habr!</h1> </body> </html> We open this page from a dev server that lives on a domain from the Microsoft compatibility list (I cannot give the domain name for obvious reasons):
Change .ru to .net
Check if meta works. Change content to "IE = EmulateIE7":
At the same time, nothing changes on .ru, IE11 remains in IE10 mode.
For the purity of the experiment, remove the tick "Use Microsoft compatibility lists":
(note, the setting of the intranet display in Compat View is disabled for the purity of the experiment, although in fact it does not change anything)
Voila, .ru is now controlled by the meta:
Carefully read the maycrosoft document:
Note that the X-UA-Compatible header has more precedence than Compatibility View.
It says only about the http-header X-UA-Compatible, about the meta-tag is not a word.
I convey greetings and sincere admiration to developers from Redmond, as well as to local world-renowned experts.
Source: https://habr.com/ru/post/201358/
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