<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
 <head>
  <title>#id and invalid IDs</title>
  <style type="text/css">
    #test\[a\] { background: orange; }
    #dup { background: orange; }
    # { background: red; }
    #\20 { background: orange; }
  </style>
 </head>
 <body>
  <ol>
   <li>id="test[a]": <span id="test[a]">TEST</span></li>
   <li>id="dup": <span id="dup">-</span><span id="dup">-</span><span id="dup">-</span><span id="dup">-</span><span id="dup">-</span></li>
   <li>id="": <span id="">TEST</span></li>
   <li>id=" ": <span id=" ">TEST</span></li>
  </ol>
 </body>
</html>
