I had some trouble with CSS on Internet Explorer 8 the other day and wondered why the hell it wasn't working.
After hours of frustration, I disabled compatibility mode by clicking on "Tools" > "Compatibility View" and it just worked.
But I had to disable this for the whole site, without having to teach each user about it. Luckily, there is a meta tag for it!
Add the following tag into the head section of your page and IE will use the specified rendering mode.
<meta http-equiv="X-UA-Compatible" content="IE=8" />
Unsure which version of Internet Explorer supports this, but I know IE8 and IE9 honours this setting.
OK, this caused a bit of confusion to me but I figured out why rounded corners (CSS border-radius) wasn't working on IE9.
I shot myself in the foot because I've set the "IE=8" compatibility mode, IE9 will not render rounded borders because IE8 doesn't actually support it.
After reading a post on StackOverflow, I looked up the docs for document compatibility and found a fix. Set the order of compatibility in this format:
<meta http-equiv="X-UA-Compatible" content="IE=9; IE=8; IE=7; IE=EDGE" />
Now it'll try IE9 mode first, IE8, then IE7. You can even set IE=EDGE so it'll use the highest mode possible.
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