Cannot read property $valid of undefined - angularjs

Question

I have a form like this -
<form name="myForm" novalidate>
There are some fields in the form which I am validating and then submitting the form like this -
<input type="button" ng-click="Save(data)" value="Save">
In the controller, I want to check if the form is not valid then Save() should show some error on the page. For that, I am setting up a watch like this -
$scope.$watch('myForm.$valid', function(validity) {
if(validity == false)
// show errors
});
But I am always getting this error on running it -
Cannot read property '$valid' of undefined
Can someone explain why?
Thanks

Answer 1

You just misspelled "myForm" in your controller code. In order to remove the error, Write "myform" instead of "myForm".
However I expect what you want is like this.
$scope.Save = function(data){
alert($scope.myform.$valid);
}
I setup jsfiddle.

Answer 2

In my case I was wrapping the form in a modal created in the controller and therefore got the same error. I fixed it with:
HTML
<form name="form.editAddress" ng-submit="save()">
<div class="form-group">
<label for="street">Street</label>
<input name="street" type="text" class="form-control" id="street" placeholder="Street..." ng-model="Address.Street" required ng-minlength="2" />
<div class="error" ng-show="form.editAddress.street.$invalid">
<!-- errors... -->
</div>
</div>
<button type="submit" class="btn btn-primary" >Save address</button>
</form>
JS
angular.module("app").controller("addressController", function ($scope, $uibModal, service) {
$scope.Address = {};
$scope.form = {};
$scope.save = function() {
if (modalInstance !== null) {
if (isValidForm()) {
modalInstance.close($scope.Address);
}
}
};
var isValidForm = function () {
return $scope.form.editAddress.$valid;
}
});