title: What regular expression does a browsers use for HTML5 input type=url?
body: <p>I'm working on a HTML5 input pattern polyfill and I'm trying to validate an input type=url in JavaScript exactly as the browser (Chrome) does but can't find any documentation on a JavaScript or PERL compatible regular expression. As it's a polyfill, I don't particularly mind if it matches all URL's exactly (which is impossible) but rather that it imitates how the browser works.</p>
  
  <p>Would anyone know of an identical pattern in PERL syntax?</p>
  
  <p>Thanks</p>