There is an extremely confusing note following the code shown in an article on the MSDN website entitled "Specifying Legacy Document Modes" - https://msdn.microsoft.com/en-us/library/jj676915(v=vs.85).aspx.
In the section, "Specifying multiple content attribute values," following the code <meta http-equiv="X-UA-Compatible" content="IE=7,9,10" >, it says: "Note: The previous example is provided for illustrative purposes only; don't use it in a production environment."
If we shouldn't actually use it, why even show it? Why even implement support for a certain code syntax, if no one should use it on production websites?
I want to achieve this exact type of result (rendering only one specific version of IE in Compatibility Mode -- in my case I want IE9 to render in IE8 document mode -- but have all other IE versions use their highest supported 'edge' document mode) -- and -- I want to use it on our production website. So I figured out the actual code I want to use is: <meta http-equiv="X-UA-Compatible" content="IE=8, IE=10, IE=11, chrome=1" />
This method would work perfectly for me, and I even tested it in IE6-11 and it does — so my only concern is that bothersome note, "don't use it in a production environment". What would even be the repercussions (if any) of using it? If I shouldn't use it, then what should I use to do the same thing?
We really need this meta tag combination for our site to work right in all versions of IE, and appears to be the only reasonable solution at the moment. It is because we have a JQuery slideshow on our site which we found to work fine in all versions of IE except for IE9 — in native IE9 doc mode, the layout falls apart. However, it was discovered that it displays normally in IE9 if we "Force IE9 to IE8 Compatibility Mode" (IE9 running in IE8 Document Mode). Currently, we are using the more simple Compatibility Mode meta tag: <meta http-equiv="X-UA-Compatible" content="IE=8" />. But the problem with this is, it renders ALL versions of IE in Compatibility Mode (IE8 document mode). This is bad for 2 reasons: It makes the newer IE versions (10 and 11) run slower because they are emulating IE8, and additionally, the newer IE versions don't display all of our intended CSS3 styles (rounded corners, drop shadows) because again, they are emulating IE8.
I am fully aware that the most ideal solution is to figure out a CSS and/or JS fix for the IE9 layout problem which would make the X-UA Compatible meta tag unnecessary — but this would require far too much trial and error, development time, and testing for us at this time — and we would not even know if we could figure out a solution.
Thank you in advance to anyone who can shed some light on this.