Do any browsers yet support HTML5's checkValidity() method?

Question

The HTML5 spec defines some very interesting validation components, including pattern (for validating against a Regexp) and required (for marking a field as required

Answer 1

Sure. Opera and Chromium. But you can test yourself:

function supportsValidity(){
  var i = document.createElement('input');
  return typeof i.validity === 'object'
}

Here's a link to a sandbox where you can see Opera and Chrome in action: http://jsfiddle.net/vaZDn/light/