@ngdoc overview @name Developer Guide: Initializing Angular: Automatic Initialization @description Angular initializes automatically when you load the angular script into your page that contains an element with `ng:app` directive:



  
    
  
  
    I can add: {{ 1+2 }}.

From a high-level view, this is what happens during angular's automatic initialization process: 1. The browser loads the page, and then runs the angular script. Angular waits for the `DOMContentLoaded` (or 'Load') event to attempt to bootstrap. 2. Angular looks for the `ng:app` directive. If found it then proceeds to compile the DOM element and its children. Optionally the `ng:app` may specify a {@link api/angular.module module} to load before the compilation. For details on how the compiler works, see {@link dev_guide.compiler Angular HTML Compiler}. ## Initialization Options The reason why `ng:app` exists is because angular should not assume that the entire HTML document should be processed just because the `angular.js` script is included. In order to compile only a part of the document set the `ng:app` on the root element of this portion. ## Global Angular Object The angular script creates a single global variable `angular` in the global namespace. All angular APIs are bound to fields of this global object. ## Related Topics * {@link dev_guide.bootstrap Initializing Angular} * {@link dev_guide.bootstrap.manual_bootstrap Manual Initialization} ## Related API {@link api/angular.module.ng.$compile Compiler API}