title: W3C error validating - Bad value for attribute href on element a: Illegal character in query: not a URL code point
body: <p>I get the bad value for attribute <code>href</code> on element <code>a</code>: Illegal character in query: not a URL code point on W3C with the following <code>a</code> tag:</p>
  
  <pre><code>&lt;a href="/edit_booking.php?requestID=84&amp;amp;moduleID=109&amp;amp;no_rooms=2&amp;amp;parks=Central,East&amp;amp;rooms=1,39&amp;amp;weeks=1,3,5,7,9,11,13,15&amp;amp;day=1&amp;amp;semester=1&amp;amp;start_time=09:00&amp;amp;end_time=10:00&amp;amp;length=1&amp;amp;students=100&amp;amp;type=Lecture&amp;amp;Priority=N&amp;amp;metaID=&amp;amp;comments=Crappy Booking&amp;amp;status=1&amp;amp;round=1&amp;amp;date_submitted=2015-02-16 05:01:17&amp;amp;year=2015/2016&amp;amp;" title="This is a link edit the booking"&gt;&lt;i class="fa fa-edit"&gt;&lt;/i&gt;&lt;/a&gt;
  </code></pre>
  
  <p>The link is generated from PHP; now if the commas are not allowed I can do a replace but I'm not sure if they are allowed in this format or not.</p>
  
  <p>Is there something I'm missing, because it looks fine to me?</p>