               <p>
                  <code class="computeroutput"><span class="identifier">Ch</span></code>
                </p>
              </td>
<td>
                <p>
                  Matches a character set <code class="computeroutput"><span class="identifier">charset</span></code>
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">alnum</span></code>
                </p>
              </td>
<td>
     