AngularJs Initializing application

Angular initializes the application using ng-app directive.
a) What is ng-app ? 
-           It will tell the AngularJS that this is the AngularJs application and the element to which directive is initialized is root element of the application. 
-           It is set in the index.html page of application directory where the <html>  </html> tags starts or in the <body></body> element.
-            Only one ng-app directive can be initialized to an element, if more than one is initialized then the first occurrence will set as the root element.
-             When the AngularJs library loads it will check the ng-app directive and set the $rootScope to the element where the ng-app is initialized.

 Example :   
   1) ng-app in HTML tag    

    <html ng-app="store">

   2) ng-app in the body tag

     <body ng-app="store">

 Code Explanation : "store" is the name of the app. you need to use the app name in your entire application.
 For ex: 

    store.controller('LoginController', function() {    


    store.filter('HTMLparser', function() {