title: Regex for http://... outside <a>
body: <p>I have a forum on which users can use the CKEditor to make links. However, some users just post the raw url, resulting in some links nice formatted and some links not.</p>
  
  <p>I'd like to make a filter based on a regex to make links of the raw urls. However, I'm stuck at making the regex. Requirements:</p>
  
  <ul>
  <li>Matches http://... in normal HTML tags (<code>&lt;b&gt;</code>, <code>&lt;p&gt;</code>, <code>blockquote</code>, ...)</li>
  <li>Does not match anything in the <code>&lt;a&gt;</code> tag</li>
  <li>Does not match anything which is an HTML attribute (<code>&lt;a href="http://..."&gt;</code>)</li>
  </ul>
  
  <p>What regex can I use?</p>