/*
 * Toggle show/hide by adding/removing the class 'hidden'
 * @param containerId where to start looking for children
 * @param className only select the children that have the provided className
*/
function toggleShowHide(containerId, className) {
  var container = document.getElementById(containerId);
  var children = container.getElementsByTagName('*');
  for(i = 0; i < children.length; i++)
  {
    var child = children.item(i);
    if(YAHOO.util.Dom.hasClass(child, className))
    {
      if(YAHOO.util.Dom.hasClass(child, 'hidden'))
      {
        YAHOO.util.Dom.removeClass(child, 'hidden');
      }
      else
      {
        YAHOO.util.Dom.addClass(child, 'hidden');
      }
    }
  }
}