@ngdoc overview @name Bootstrap @sortOrder 350 @description # Bootstrap This page explains the AngularJS initialization process and how you can manually initialize AngularJS if necessary. ## AngularJS ` ``` 1. Place the `script` tag at the bottom of the page. Placing script tags at the end of the page improves app load time because the HTML loading is not blocked by loading of the `angular.js` script. You can get the latest bits from http://code.angularjs.org. Please don't link your production code to this URL, as it will expose a security hole on your site. For experimental development linking to our site is fine. * Choose: `angular-[version].js` for a human-readable file, suitable for development and debugging. * Choose: `angular-[version].min.js` for a compressed and obfuscated file, suitable for use in production. 2. Place `ng-app` to the root of your application, typically on the `` tag if you want AngularJS to auto-bootstrap your application. 3. If you choose to use the old style directive syntax `ng:` then include xml-namespace in `html` when running the page in the XHTML mode. (This is here for historical reasons, and we no longer recommend use of `ng:`.) ## Automatic Initialization

AngularJS initializes automatically upon `DOMContentLoaded` event or when the `angular.js` script is evaluated if at that time `document.readyState` is set to `'complete'`. At this point AngularJS looks for the {@link ng.directive:ngApp `ngApp`} directive which designates your application root. If the {@link ng.directive:ngApp `ngApp`} directive is found then AngularJS will: * load the {@link guide/module module} associated with the directive. * create the application {@link auto.$injector injector} * compile the DOM treating the {@link ng.directive:ngApp `ngApp`} directive as the root of the compilation. This allows you to tell it to treat only a portion of the DOM as an AngularJS application. ```html I can add: {{ 1+2 }}. ``` As a best practice, consider adding an `ng-strict-di` directive on the same element as `ng-app`: ```html I can add: {{ 1+2 }}. ``` This will ensure that all services in your application are properly annotated. See the {@link guide/di#using-strict-dependency-injection dependency injection strict mode} docs for more. ## Manual Initialization If you need to have more control over the initialization process, you can use a manual bootstrapping method instead. Examples of when you'd need to do this include using script loaders or the need to perform an operation before AngularJS compiles a page. Here is an example of manually initializing AngularJS: ```html

Hello {{greetMe}}!

``` Note that we provided the name of our application module to be loaded into the injector as the second parameter of the {@link angular.bootstrap} function. Notice that `angular.bootstrap` will not create modules on the fly. You must create any custom {@link guide/module modules} before you pass them as a parameter. You should call `angular.bootstrap()` *after* you've loaded or defined your modules. You cannot add controllers, services, directives, etc after an application bootstraps.

**Note:** You should not use the ng-app directive when manually bootstrapping your app.

This is the sequence that your code should follow: 1. After the page and all of the code is loaded, find the root element of your AngularJS application, which is typically the root of the document. 2. Call {@link angular.bootstrap} to {@link compiler compile} the element into an executable, bi-directionally bound application. ## Things to keep in mind There are a few things to keep in mind regardless of automatic or manual bootstrapping: - While it's possible to bootstrap more than one AngularJS application per page, we don't actively test against this scenario. It's possible that you'll run into problems, especially with complex apps, so caution is advised. - Do not bootstrap your app on an element with a directive that uses {@link ng.$compile#transclusion transclusion}, such as {@link ng.ngIf `ngIf`}, {@link ng.ngInclude `ngInclude`} and {@link ngRoute.ngView `ngView`}. Doing this misplaces the app {@link ng.$rootElement `$rootElement`} and the app's {@link auto.$injector injector}, causing animations to stop working and making the injector inaccessible from outside the app. ## Deferred Bootstrap This feature enables tools like [Batarang](https://github.com/angular/angularjs-batarang) and test runners to hook into angular's bootstrap process and sneak in more modules into the DI registry which can replace or augment DI services for the purpose of instrumentation or mocking out heavy dependencies. If `window.name` contains prefix `NG_DEFER_BOOTSTRAP!` when {@link angular.bootstrap} is called, the bootstrap process will be paused until `angular.resumeBootstrap()` is called. `angular.resumeBootstrap()` takes an optional array of modules that should be added to the original list of modules that the app was about to be bootstrapped with.