Validating check boxes and radio buttons with Prototype
The title might be misleading, but the kind of validation I was after is checking whether or not at least one option in a group of elements (check boxes or radio buttons) is checked.
This is useful in cases where you want the user to make a choice on their own instead of accepting a default value, or in cases where you can’t supply a default one. I wanted the validation to take place at client-side, before posting the form, so JavaScript is the only option.
I tried different approaches to this matter, but wound up with using the Prototype JavaScript framework which allowed me to construct an efficient little one-liner:
Replace the elements selector with your own. Just make sure it returns a collection of checkboxes or radio buttons. It will return boolean true if at least one of the elements is checked, otherwise false.
