exemplo 6.5 – scope-directive-bindings-twoway.html

  <!doctype html>
  <html ng-app="myApp">
  <body ng-controller="ParentController">
    <div>
      <span>Parent Count: {{parentCount}}</span><br />
      <div my-dir count="parentCount" />
    </div>
  <script src="angular.min.js"></script>
  <script type="text/javascript">
   angular.module('myApp', [])
  .controller('ParentController', function($scope) {
    $scope.parentCount = 1; // scope Pai
  })
  .directive('myDir', function() {
    return {
      scope: {
        count: "="
      },
      link: function(scope, ele, attrs) {
      var button = angular.element('<button>Increment ParentController count through Directive</button>');

      button.on('click', function(){
        scope.$apply(function(){
          scope.count++;
        });
      });
      
      ele.append(button);
    }
   };
  });
  </script>
  </body>
  </html>