@ngdoc overview
@name Developer Guide: Bootstrap
@description
# Overview
This page explains the Angular initialization process and how you can manually initialize Angular
if necessary.
## Angular `<script>` Tag
This example shows the recommended path for integrating Angular with what we call automatic
initialization.
<pre>
<!doctype html>
<html xmlns:ng="http://angularjs.org" ng-app>
<body>
...
<script src="angular.js">
</body>
</html>
</pre>
* 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 {@link 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.
* Place `ng-app` to the root of your application, typically on the `<html>` tag if you want
angular to auto-bootstrap your application.
<html ng-app>
* If IE7 support is required add `id="ng-app"`
<html ng-app id="ng-app">
* If you choose to use the old style directive syntax `ng:` then include xml-namespace in `html`
to make IE happy. (This is here for historical reasons, and we no longer recommend use of
`ng:`.)
<html xmlns:ng="http://angularjs.org">
## Automatic Initialization
Angular 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 Angular looks
for the {@link api/ng.directive:ngApp `ng-app`} directive which designates your application root.
If the {@link api/ng.directive:ngApp `ng-app`} directive is found then Angular will:
* load the {@link guide/module module} associated with the directive.
* create the application {@link api/AUTO.$injector injector}
* compile the DOM treating the {@link api/ng.directive:ngApp
`ng-app`} directive as the root of the compilation. This allows you to tell it to treat only a
portion of the DOM as an Angular application.
<pre>
<!doctype html>
<html ng-app="optionalModuleName">
<body>
I can add: {{ 1+2 }}.
<script src="angular.js"></script>
</body>
</html>
</pre>
## 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 Angular compiles a page.
Here is an example of manually initializing Angular:
<pre>
<!doctype html>
<html xmlns:ng="http://angularjs.org">
<body>
Hello {{'World'}}!
<script src="http://code.angularjs.org/angular.js"></script>
<script>
angular.element(document).ready(function() {
angular.bootstrap(document, ['optionalModuleName']);
});
</script>
</body>
</html>
</pre>
Note that we have provided the name of our application module to be loaded into the injector as the second
parameter of the {@link api/angular.bootstrap} function. This example is equivalent to using the
{@link api/ng.directive:ngApp ng-app} directive, with `ng-app="optionalModuleName"`, as in the automatic
initialization example above.
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 api/angular.bootstrap} to {@link compiler compile} the element into an
executable, bi-directionally bound application.