[Solved] Why doesn’t most simple case of Angular’s ng-show work?

Your JSFiddle is not using Angular at all so there’s no code doing anything with your DIV. You have to reference the framework in order to use it.

Add a <SCRIPT> reference to angular.js and then do something like this:

<div ng-app> <!-- this initializes angular and hooks the framework -->
  AAAA
  <div ng-show="false">
       XXXXX
  </div>
  BBBBBBB
</div>

I forked your JSFiddle so you can see it working.