The following piece of JS which used to work in IE8 is failing now in IE9.
document.createElement(\'
The API for createElement specifies that the constructor wants a string that species the name of an element. It would appear that IE9 is more strictly following standards. You can accomplish the same thing you are trying to do with the following code:
var iframe = document.createElement("iframe");
iframe.setAttribute("id", "yui-history-iframe");
iframe.setAttribute("src", "../../images/defaults/transparent-pixel.gif");
iframe.setAttribute("style", "position:absolute;top:0;left:0;width:1px;height:1px;visibility:hidden;");
http://msdn.microsoft.com/en-us/library/ms536389(v=vs.85).aspx