Since IE8 released a 2400 site list that warns their site is going to be doomed, MSN China included, everyone’s scrambling to make sure that their sites don’t break.
A way to prevent doomsday is to keep asking IE8 to behave like IE7. So IE came up with a brilliant idea to do this.
On a per-site basis, site owners need to add a custom HTTP header [1]
X-UA-Compatible: IE=EmulateIE7
While on a per-page basis, a meta tag is added
http-equiv="X-UA-Compatible" content="IE=EmulateIE7"
However, since everyone is trying to prevent their site to look like a dog’s breakfast, everyone starts throwing in “X-UA-Compatible: IE=EmulateIE7″
Hallvord tried putting this trend to the test. He checks out what happen when everyone starts throwing this tag (even big software company!). We get some lovely results with IE=EMulateIE7.
Now, I think Microsoft’s attempt to finally opt-in standards deserved praise (despite the fact that they single-handedly created the standards divide prior). X-UA-Compatible presents a fair way for site owners to mitigate the issue while they update their site to standards compatible.
What we don’t want to see is for X-UA-Compatible to become a permanent residue in our HTML page-something that everyone includes just for the sake of including.
The X-UA-Compatible meta/header tag should only be included when your page doesn’t render correctly with IE8 standards mode. Why throw in some fancy tags when you don’t need them?
Resources:
[1] http://msdn.microsoft.com/en-us/library/cc817574.aspx