Angularjs Form/Field validation using JavaScript function without directives

Question

Is there a way to validate a field in angular without using a directive? For example: I want to make following validation on an input field.

Answer 1

I'm surprised no one has mentioned ui-validate

$scope.isOdd = function($value){
  return $value % 2;
}
...

  
  
{{myform.value.$error|json}}

Doesn't get any simpler than that, and it's PROPER AngularJS validation (not silly watches)

Here's a working demo