AngularJS日期输入未在Firefox的指令中显示初始值

<input type="date" ng-model="selectedDate">

app.controller('myController', function($scope) {
  $scope.selectedDate = new Date();
});

<input type="date" ng-model="selectedDate" ng-init="selectedDate = new Date()">

app.directive('initialDate', function() {
  return {
    restrict: 'A',
    link: function(scope, element, attrs) {
      scope.selectedDate = new Date();
    }
  };
});

<input type="date" ng-model="selectedDate" initial-date>