Internet Explorer 11 detection

Edit 18 Nov 2016

This code also work (for those who prefer another solution , without using ActiveX)

var isIE11 = !!window.MSInputMethodContext && !!document.documentMode;
  // true on IE11
  // false on Edge and other IEs/browsers.

Original Answer

In order to check Ie11 , you can use this : ( tested)

(or run this)

!(window.ActiveXObject) && "ActiveXObject" in window

I have all VMS of IE :

Notice : this wont work for IE11 :

as you can see here , it returns true :

So what can we do :

Apparently , they added the machine bit space :

ie11 :

"Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; .NET4.0E; .NET4.0C; .NET CLR 3.5.30729; .NET CLR 2.0.50727; .NET CLR 3.0.30729; rv:11.0) like Gecko"

ie12 :

"Mozilla/5.0 (Windows NT 6.3; Win64; x64; Trident/7.0; .NET4.0E; .NET4.0C; .NET CLR 3.5.30729; .NET CLR 2.0.50727; .NET CLR 3.0.30729; rv:11.0) like Gecko"

so we can do:

/x64|x32/ig.test(window.navigator.userAgent)

this will return true only for ie11.

To detect MSIE (from version 6 to 11) quickly:

if(navigator.userAgent.indexOf('MSIE')!==-1
|| navigator.appVersion.indexOf('Trident/') > -1){
   /* Microsoft Internet Explorer detected in. */
}

I use the following function to detect version 9, 10 and 11 of IE:

function ieVersion() {
    var ua = window.navigator.userAgent;
    if (ua.indexOf("Trident/7.0") > -1)
        return 11;
    else if (ua.indexOf("Trident/6.0") > -1)
        return 10;
    else if (ua.indexOf("Trident/5.0") > -1)
        return 9;
    else
        return 0;  // not IE9, 10 or 11
}  

All of the above answers ignore the fact that you mention you have no window or navigator :-)

Then I openede developer console in IE11

and thats where it says

Object not found and needs to be re-evaluated.

and navigator, window, console, none of them exist and need to be re-evaluated. I've had that in emulation. just close and open the console a few times.