Chapter 9: Trimming your watch list with lazy binding
HTML
<script src="https://code.angularjs.org/1.3.2/angular.min.js"></script>
<div ng-app="myApp">
<input ng-model="user.name" />
{{ ::user.name }}
</div>
JavaScript
angular.module('myApp', [])
.controller('cont',function($scope){
$scope.$watch('$scope.user.name',function(){alert('asi');});
});