public ActionResult Add(Comment comment)
        {
            _db.Comments.Add(comment);

            _db.SaveChanges();

            return Json(comment.Id);  
        }

  $scope.addComment = function () {

        $http.post("/Comment/Add", $scope.comment).success(function (id) {

            $scope.comments.push({Id:id ,Name: $scope.comment.Name, CommentBody: $scope.comment.CommentBody });

            $scope.comment = {};

        });
    };

var token = $('[name=__RequestVerificationToken]').val();
data.__RequestVerificationToken = token;
...
...
...
 $.ajax({
  url: url,
  type: "POST",
  data: data
});