angular 倒计时

$scope.countdown = ;
var myTime = setInterval(function() {
                                 $scope.countdown--;
                                 $scope.$digest(); // 通知视图模型的变化
                                 }, );

// 倒计时10-0秒，但算上0的话就是11s
setTimeout(function() {
               　　// Do SomeThing

                   clearInterval(myTime);
                   $scope.countdown.$destroy();
}, );

  $scope.countdown="获取验证码";
     $scope.countdownEvent=function(){
        $scope.countdown=;
        var myTime=setInterval(function(){
               if($scope.countdown>){
                $scope.countdown--;
               }else{
                 $scope.countdown="获取验证码";
                 clearInterval(myTime);
               }
        },);
     }

 var myinterval;
    $scope.countdown = 10;
    $scope.aa=function(){
           $scope.countdown = 10;
           mytimeout=$interval(function(){
              if($scope.countdown>1){
                $scope.countdown--;
              }else{
                $interval.cancel(mytimeout);
                $scope.countdown = 10;
              }
            },1000);
    }