<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8"/>
    <title>Example</title>
    <script type="application/its+xml">
     <its:rules  xmlns:its="http://www.w3.org/2005/11/its"  xmlns:h="http://www.w3.org/1999/xhtml" version="2.0">
      <its:param name="acParam">name</its:param>
      <its:allowedCharactersRule allowedCharacters="[a-zA-Z_\-]" selector="//h:code[@id=$acParam]"/>
     </its:rules>
    </script> 
  </head>
  <body>
    <p>Login names can only use letters from A to Z (upper or lowercase)
    and the character underscore (_) and minus (-).
    For example: <code id="name">Huck_Finn</code>.</p>
  </body>
</html>