Check this link:
JavaScript Window Navigator[
^]
It will show you how to get all the information available to you via JavaScript and also will show you how untrustworthy that info is...
For instance 'Netscape' is the application name fro IE11, Chorme and Firefox...
Or 'Mozilla' is the application code name for IE, Chrome, Firefox...
So not getting the browser name is not your fault, the question is why in the first place you looked for it?