internet explorer 10 - Detect IE compatibility-mode with only PHP

Question

Is it possible to detect that IE is in compatibility mode from the useragent with PHP?

I use IE10 and have the useragent

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/6.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)

So it appears as Internet Explorer 7 then.

Sure, It would be a bad idea to rely on only such a detection by PHP, but it is very useful for some ocasions (for example logging with PHP or debugging-hints,...)

Answer 1

From this resource: http://msdn.microsoft.com/en-us/library/ie/hh869301(v=vs.85).aspx

To detect IE 10 in compatibility mode rather than a regular IE 7 you should look at the token Trident/6.0 which identifies IE 10 regardless of the mode.

To detect it from PHP, grab the user agent from the headers and parse it for the Trident/6.0 string token.

You can recognize more versions of Internet Explorer from the Trident token: IE9 has Trident/5.0, IE 8 has Trident/4.0, IE 7 has no Trident in it's user agent.

The user agent string can be found at $_SERVER['HTTP_USER_AGENT']. From there it's trivial as to search a substring inside or with a regex.

IE10 User agent reference:

• normal mode: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)
• compatibility mode: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.2; Trident/6.0)

Note that the MSIE token is different but the Trident token is the same. This is the indication that the user has compatibility mode enabled.