Ext.isIE return false in IE 11

extjs, extjs4.2

Solution

IE 11 is not officially supported prior to ExtJS 4.2.2 (see property `isIE11`). Microsoft removed the `MSIE` part from IE11's user agent (refer here), which is the reason why it does not work with ExtJS 4.2.1 and below.

From the source code, for ExtJS 4.2.1:

isIE = !isOpera && check(/msie/),
isIE7 = isIE && ((check(/msie 7/) && docMode != 8 && docMode != 9 && docMode != 10) || docMode == 7),
isIE8 = isIE && ((check(/msie 8/) && docMode != 7 && docMode != 9 && docMode != 10) || docMode == 8),
isIE9 = isIE && ((check(/msie 9/) && docMode != 7 && docMode != 8 && docMode != 10) || docMode == 9),
isIE10 = isIE && ((check(/msie 10/) && docMode != 7 && docMode != 8 && docMode != 9) || docMode == 10),
isIE6 = isIE && check(/msie 6/),

and for ExtJS 4.2.2:

isIE = !isOpera && (check(/msie/) || check(/trident/)),
isIE7 = isIE && ((check(/msie 7/) && docMode != 8 && docMode != 9 && docMode != 10) || docMode == 7),
isIE8 = isIE && ((check(/msie 8/) && docMode != 7 && docMode != 9 && docMode != 10) || docMode == 8),
isIE9 = isIE && ((check(/msie 9/) && docMode != 7 && docMode != 8 && docMode != 10) || docMode == 9),
isIE10 = isIE && ((check(/msie 10/) && docMode != 7 && docMode != 8 && docMode != 9) || docMode == 10),
isIE11 = isIE && ((check(/trident\/7\.0/) && docMode != 7 && docMode != 8 && docMode != 9 && docMode != 10) || docMode == 11),
isIE6 = isIE && check(/msie 6/),

Problem

When I try to use Ext.isIE in IE11 i get false the returning value. And then during the debug my code I see that I get the following error: JavaScript Error - Msg:Invalid argument., my extjs's version is: 4,2

Original source