title: Input element inside anchor element
body: <p>I have a form like this:</p>
  
  <pre><code>&lt;form id="cars" action="file.php" method="post"&gt;
  &lt;a href="#" onclick="document.getElementById('cars').submit();"&gt;&lt;input type="hidden" value="ford" name="model" /&gt;Ford&lt;/a&gt;
  &lt;a href="#" onclick="document.getElementById('cars').submit();"&gt;&lt;input type="hidden" value="toyota" name="model" /&gt;Toyota&lt;/a&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>However, the <code>$_POST['model']</code> gave error "Undefined index: model". What's wrong with that?</p>