<!doctype html>
<html class="a">
 <head>
  <title>document.getElementsByClassName(): changing classes</title>
  <script src="resources/common.js"></script>
 </head>
 <body class="a">
  <p id="r">FAIL (script did not run)</p>
  <script>
   var collection = document.getElementsByClassName("a")
   document.body.className += "\tb"
   t(collection, [document.documentElement, document.body])
  </script>
 </body>
</html>