Using the ValidationProperty I’ve managed to connect a RequiredFieldValidator with my custom control. When I enable client script in the validator, JavaScript errors occur.
Is there a way to tell the RequiredFieldValidator how it can validate my custom control in the client?
In the first instance ensure the ControlToValidate property is pointing at the control you wish to validate.
Worryingly the JavaScript error is a bit weird as using RequiredFieldValidator would emit the stock ASP.NET validation code.
You could used a Custom Validator where you define the JavaScript method you want to execute to perform the validation.