script.js

  angular.module('docsTimeDirective', [])
    .controller('Ctrl2', function($scope) {
      $scope.format = 'M/d/yy h:mm:ss a';
    })
    .directive('myCurrentTime', function($interval, dateFilter) {

      function link(scope, element, attrs) {
        var format,
            timeoutId;

        function updateTime() {
          element.text(dateFilter(new Date(), format));
        }

        scope.$watch(attrs.myCurrentTime, function(value) {
          format = value;
          updateTime();
        });

        element.on('$destroy', function() {
          $interval.cancel(timeoutId);
        });

        // start the UI update process; save the timeoutId for canceling
        timeoutId = $interval(function() {
          updateTime(); // update DOM
        }, 1000);
      }

      return {
        link: link
      };
    });