Automatic Initialization of Angular does not seem to work

I was following the Automatic Initialization of Angular.js (based on their example) I made a basic html file, with the following contents:

<!doctype html>
<html ng-app="optionalModuleName">
  <body>
    I can add: {{ 1+2 }}.
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.5/angular.min.js"></script>
   </body>
</html>

Unfortunately, this does not seem to work on my browser. If I add the following script (Manual Initialization), it works.

<script>
  angular.element(document).ready(function() {
  angular.bootstrap(document);
});
</script>

I was wondering why automatic initialization did not work. Any ideas?

You do not seem to have an optionalModuleName defined :-)