Facebook is having allot of JavaScript issues at the moment in Internet Explorer (IE 9), however by clicking the IE 8 Compatibility Mode button, or by switching to IE 8 Compatibility via the Developer tools you can get rid of all the JavaScript errors.
My apps are using the newer iFrame method, I have tried the following tags:
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />
<meta http-equiv="X-UA-Compatible" content="IE=IE8" />
Neither seemed to switch the parent frame into the correct mode (document.documentMode != 8), is there a way to force IE 9 into Compatibility mode for the whole site (facebook.com) from within a iFrame either via JavaScript or some undocumented method?