Angular JS - SPA field validation

I am using SPA,I was trying to make this field is mandatory when we click on save button but it's saving as null, Here I am using ng-form but not form

Here is my code:

event.html:

<div ng-form="eventForm" class="modal-content">
    <div class="form-group">
        <label>Place*</label> <input type="text" class="form-control" required
            name="eventPlace" id="eventPlace" ng-model="eventVO.eventPlace" />
        <div ng-show="eventForm.eventPlace.$touched">
            <span ng-show="eventForm.eventPlace.$error.required">This
                field is required.</span>
        </div>
    </div>
    <a class="btn btn-success" ng-click="saveEvent()"
        title="Click to save event">Save</a>
</div>

EventController.js:

$scope.saveEvent = function() {
            debugger;
            $scope.eventVO.userId = Session.userId;
            $scope.eventVO.eventStartDate = moment($scope.eventVO.eventStartDate).format('YYYY-MM-DD HH:mm a');
            $http({
                url : "/event/add",
                method : 'POST',
                dataType : 'json',
                'headers' : {
                    'Content-Type' : 'application/json'
                },
                data : $scope.eventVO
            }).then(function(dataResponse) {
                debugger;
                if (dataResponse.data.status == "success") {
                    notify('Event saved successfully');
                    $(".add-event-modal").modal("hide");
                    $scope.getEvents();
                    $scope.clearModal();
                } else {
                    notify('Error occured While Saving Event');
                }
            });
        };

It is showing that 'This field is required' but saving when we click on Save button. How to make this field mandatory?

Note: Here I am not using submit when click on save.