title: AngularJS tags attributes
body: <p>I am learning about AngularJS and see it adds some of its own attributes that nor start with data neither are standard html tags attributes, like this:</p>
  
  <pre><code>&lt;html ng-app&gt;
  </code></pre>
  
  <p>or this:</p>
  
  <pre><code>&lt;body ng-controller="PhoneListCtrl"&gt;
  </code></pre>
  
  <p>Where from do these ng-* attributes come and is that a valid HTML? Where can I read more about this?</p>