/**
*  This function expands or collapses the given submenu
*
*  \param  item_id  The DOM id of the subsection to be toggled
*/
function toggleMenu(item_id) {
 

  // Get the handle to the item
  var section = document.getElementById(item_id);
  // Get the handle to the parent of the item
  var parent_section = document.getElementById('parent_' + item_id);
  // Make sure that this section should be toggled
  if ((parent_section.className != 'jmenu_section_image_nosub') && (parent_section.className != 'jmenu_section_image_nosub_active')){
    // Toggle the item
    if (section.style.display != 'none') {
      // Hide the section
      section.style.display = 'none';
      // Show the plus image
      parent_section.className = 'jmenu_section_image_contracted';
    }  else {
      // Show the section
      section.style.display = '';
      // Show the minus image
      parent_section.className = 'jmenu_section_image_expanded';
    }
  } else {
    parent_section.className = 'jmenu_section_image_nosub_active';
  }

}