title: If input field is empty show div
body: <p>I'd like to show the <strong>div</strong> with <strong>id="showDiv"</strong>, but only if the <strong>input</strong> field with <strong>id="textfield"</strong> is empty.</p>
  
  <pre><code>&lt;form action=""&gt;
   &lt;fieldset&gt;
    &lt;input type="text" id="textfield" value=""&gt;
   &lt;/fieldset&gt;
  &lt;/form&gt;
  
  &lt;div id="showDiv" style="width:50px;height:50px;background-color:#6CF;"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>Anyone know a Javascript that can do this? </p>