In this we will discuss about Directives. Directives are core features of AngularJS.
Directive is introduced as a new syntax. They are markers on a DOM element which have a special behavior to it. Just for an example only HTML don't know how a date picker will perform, so for that we need directives.
AngularJS directives controls the rendering of HTML inside an AngularJS application. You can implement your own directives too.
Here are main four types of directives:
CSS class directives
The directive initializes an AngularJS application. the ng-app describe in the root element for example in html or body start tag, and it tells angularJs that div or element are owner of angular application. Only one AngularJS application can be auto-bootstrapped per HTML document.