title: how to filter texts with a url inside using Regular Expressions?
body: <p>I want to filter the input text if it's got A URL inside it.
  By URL I mean that every thing that corresponds to a valid internet address like <code>www.example.com</code>, <code>example.com</code>, <code>http://www.example.com</code>, <code>http://example.com/foo/bar</code>.</p>
  
  <p>I think I've gotta use regular expressions and the <code>preg_match</code> function so I need the correct regexp pattern for this purpose.<br>
  I'd be very grateful if anybody could give me that.</p>