I have a form with a <textarea required>, <input type="checkbox">, <input type="text">, and <button type="submit">.
It's all fancified with jQuery, so that if you're in the text-input, or tab to the checkbox, and hit Enter, I catch that and preventDefault so the form doesn't submit.
But I want the form to be equally sensible for people who aren't running Javascript. Surely there is some markup or CSS to indicate that a given form element shouldn't cause form submission?