Check if user is using IE in compatibility mode

Question

I am looking for some code (PHP or JavaScript) that would work well to check if a user is using pageview compatibility mode.

I can then use this code to execute some conditional statements or basically give them a notification to disable it.

Answer 1

Forced:

<meta http-equiv="X-UA-Compatible" content="IE=edge" /> 

This will disable the compatibility view if the user does not start it and disable it by going to the Developer Tools and changing it.

Answer 2

I use:

 try{ JSON } catch (e){ alert("Compatibility Mode Detected") }