When the 'validationMessage' custom binding is used in an element, and that element is later removed from the DOM, if the validation is triggered an error is thrown. This PR fixes that problem by checking on whether the element has a parent node before updating it, and by disposing the subscription that updates the element when the element is disposed.
…und was "construction"
* Matches Reach's behavior, allowing input fields to have a red border when the validation fails.
* Also adds a configuration to allow the validation to run only on input changes, if desired.
…the need to bind it on the page