title: Bootstrap collapse vertical toggle switch
body: <pre><code>$('#demo').on('hidden', function () {
      $('#divbody').removeClass('span4').addClass('span8');
  });
  </code></pre>
  
  <p>
  
  <p>When the <code>button</code> is clicked: the <code>demo</code> div collapses vertically (i.e. width = 0) which works fine. But I want to then increase the <code>divbody</code> div to fill the page i.e. <code>span8</code>. The JS code is there but I want to do it animation like when the <code>demo</code> div collapses. </p>