title: Place of ng-app in html tags
body: <p>I'm new to AngularJS. My lecturer said ng-app can use in html, body, div tags etc. My question is, if ng-app can use in html tag and body tag, is there a any use if i use it in html tag rather than body tag? 
  What I mean is, the head tag is middle of body and html. Is there any effect cause in head tags when I use it html tag or not. hope my question is clear.</p>