title: preg_match('/[a-z0-9\-]+/i', $u) $ Sign
body: <p>When I submit this form I keep getting a match which it shouldn't do. I know it has something to do with the dollar sign but I can't work out the combination and I can't seem to find the right answer on Google.</p>
  
  <pre><code>&lt;?php
  if ( isset( $_POST['test'] ) ) {
      $u = $_POST['test'];
      echo preg_match('/[a-z0-9\-]+/i', $u);
  }
  ?&gt;
  
  &lt;form method="post"&gt;
      &lt;input type="text" name="test" value="12$abc213"&gt;
      &lt;button type="submit"&gt;Submit&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>