id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
11182	[IE11] Editor crashes when IE works in Quirks Mode	Mathieu Marcotte	Piotrek Koszuliński	"core/env.js contains the following lines :

{{{
                // Internet Explorer 6.0+
                if ( env.ie ) {
                        // We use env.version for feature detection, so set it properly.
                        if ( env.quirks || !document.documentMode )
                                version = parseFloat( agent.match( /msie (\d+)/ )[ 1 ] );
                        else
                                version = document.documentMode;
}}}

I am getting a crash on ""version = parseFloat( agent.match( /msie (\d+)/ )[ 1 ] );"". The reason is that the Internet Explorer 11 user agent string does not contain the word ""MSIE"".

(The reason why it enters this ""if"" at all if because 'env.quirks' is true, although I am unusre why it would be the case, I have verified and the web page is running in ""Edge"" document mode. So maybe the real bug is incorrect detection of quirks mode?)

"	Bug	closed	Normal	CKEditor 4.3.1	General	4.3	fixed