AngularJS 1.4.x

var app = angular.module('plunker', []);

app.controller('Parent', function($scope) {
    $scope.greeting = "Hello World!";
});

app.controller('Child', function($scope) {
});

<!DOCTYPE html>
<html ng-app="plunker">

  <head>
    <meta charset="utf-8" />
    <title>AngularJS Plunker</title>
    <script>document.write('<base href="' + document.location + '" />');</script>
    <link rel="stylesheet" href="style.css" />
    <script data-require="angular.js@1.4.x" src="https://code.angularjs.org/1.4.3/angular.js" data-semver="1.4.3"></script>
    <script src="app.js"></script>
  </head>

  <body ng-controller="Parent">
    parent <input type="text" ng-model="greeting">
    <div ng-controller="Child">
      child <input type="text" ng-model="greeting">
    </div>
  </body>
</html>

/* Put your css in here */