Angular initializes automatically DOMContentLoaded event or when you download angular.js script is to the browser.
After this, AngularJS find the ng-app directive that is the root of angular app compilation. When ng-app directive is found, AngularJS do the following steps:
1) load the module, which is associated with the directive,
2) Create application injector,
3) Compile the DOM from the ng-app root element. This process is known as auto bootstrapping.
anand.johari1994