title: Show submit button if checked
body: <p>I need to hide the submit button if none checkboxes is checked.
  if at least one is checked the submit button should be displayed.
  I use JQuery.</p>
  
  <pre><code>&lt;input type="checkbox" name="prog" value="1"&gt;
  &lt;input type="checkbox" name="prog" value="2"&gt;
  
  &lt;input type="submit" id="submit_prog" value='Submit' /&gt;
  </code></pre>
  
  <p>EDIT</p>
  
  <p>How can I combine it with a "check all" checkbox?</p>