angular apply

 <div ng-controller="firstController">

  {{date}}

 </div>

 <script>
     var firstController = function($scope){
         $scope.date = new Date();

       setInterval(function(){
           $scope.$apply(function(){
               $scope.date = new Date()
               //会去触发脏检查 用于自定义
           })
       },1000)
            //controller最后会自动触发脏检查
     }