How does the regular expression match 3 in JavaScript?
<p>This is a statement from JavaScript regular expression description:</p>

<blockquote>
  <p><code>^</code> has a different meaning when it appears as the first character in a character set pattern.<br>
  For example, <code>/[^a-z\s]/</code> matches the <code>'3'</code> in <code>"I have 3 sisters"</code>.</p>
</blockquote>

<p>How does <code>^</code> match <code>3</code>?</p>
