>
      <dd>Values in any base may have fraction digits.</dd>
      <dd>
        In bases above 10, numerals above 9 are represented by lower-case
        letters.
      </dd>
    </dl>
    <dl>
      <dt><code>base</code></dt>
      <dd>
        <i>number</i> : integer, <code>2</code> to <code>36</code> inclusive
      </dd>
      <dd>The base of <code>value</code>.</dd>
      <dd>If <code>base</code> is omitted, or is <code>null</code> or undefined,
      base 10 is assumed.</dd>
    </dl>
    <p>Returns 