title: mootools show/hide div dependent on whether or not checkbox is checked
body: <p>I have a checkbox I wanting to show a fieldset in a form dependent on whether or not the checkbox is clicked or not? i.e if the checkbox is checked don't show the fieldset and if it is not show the fieldset.</p>
  
  <p>My markup looks like this, </p>
  
  <pre><code>&lt;fieldset class="toplined"&gt;
  &lt;label&gt;Keep Image&lt;/label&gt;
  &lt;input type="checkbox" name="update_image[]" value="1" id="toggle" checked='true'/&gt;
  &lt;/fieldset&gt;
  
  &lt;fieldset class="toplined toggle_slide"&gt;
  &lt;label&gt;Image:&lt;/label&gt;
  &lt;input type="file" name="article_image[]"&gt;
  &lt;/fieldset&gt;
  </code></pre>
  
  <p>the fieldset with the class toggle_slide is the one I want to show/hide, I currently have this mootools script</p>
  
  <pre><code>$('toggle').addEvent('click', function(e){
      e = new Event(e);
      $$('.toplined toggle_slide').toggle();
      e.stop();
  });
  </code></pre>
  
  <p>however this just results in errors.</p>