title: Event in HTML5 form raised before validation of input fields.
body: <p>Is there any event raised before the validation of fields in an HTML5 form and before the submit of this form?</p>
  
  <p>AFAIK, the submit event is raised just before the submit of the form, but after the validation step, so this one fires too late for me.</p>
  
  <p><strong>Update</strong>: I have a textarea with the "required" property, and if the user has JS I want to substitute it by an HTML editor. The HTML editor syncs its contents with the textarea on submit (after the validation step), so for the browser the textarea is always empty. That's why I'm asking for an event fired before the validation. Any other way answer that solves this problem will be accepted.</p>