title: Hide div remove value
body: <p>how to not submit value when div is hide? I'm using calendar fill.
  if I show it, we can choose a date and send it to database and if hide it.
  i wont send a value to database or the value is "no data".</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  function showMe (it, box) {
  var vis = (box.checked) ? "block" : "none";
  document.getElementById(it).style.display = vis;}
  &lt;/script&gt;
  </code></pre>