title: regex for url some issue
body: <p>i wrote regex to validate url, it works fine for most of url i for below url it does not works:</p>
  
  <p>my regex :</p>
  
  <pre><code>/^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([?=\/\w \.-]*)\/?$/
  </code></pre>
  
  <p><a href="https://www.facebook.com/permalink.php?story_fbid=802451379821615&amp;id=298161773583914&amp;pnref=story" rel="nofollow">https://www.facebook.com/permalink.php?story_fbid=802451379821615&amp;id=298161773583914&amp;pnref=story</a></p>
  
  <p>how to make it work for all urls </p>