function toogleDisplay(el)
{
  //var el = document.getElementById(obj);
  if ( el.style.display != 'none' )
  {
    el.style.display = 'none';
  }
  else
  {
    el.style.display = '';
  }
}

function collapseMenus()
{
  var menu = document.getElementById('menu');
  var spans = menu.getElementsByTagName('span');
  var divs = menu.getElementsByTagName('div');
  //convert HTMLCollections into arrays.
  //See http://www.byteclub.net/wiki/Javascript_getElementsByTagName
  var menus = new Array();
  var submenus = new Array();
  //in the process, remove undesired elements, which get in the way somehow.
  for (i in spans)
    if(spans[i].tagName == "SPAN")
      menus[menus.length] = spans[i];
  for (j in divs)
    if(divs[j].tagName == "DIV")
      submenus[submenus.length] = divs[j];
  if (menus.length != submenus.length)
    alert('Incorrect source code: different number of menus ('+
        + menus.length+') and submenus('+submenus.length+')');
  else for(k in menus)
  {
    toogleDisplay(submenus[k]);
    makeMenu(menus[k],submenus[k]);
  }
}

function makeMenu(linkyspan,submenu)
{
  //var linkyspan = document.getElementById('havedonelink');
  linkyspan.tabIndex="0";
  linkyspan.onmouseover = function () {this.style.cursor='pointer'; this.style.textDecoration='underline';}
  linkyspan.onmouseout = function () {this.style.textDecoration = 'none'; }
  linkyspan.onclick = function () {toogleDisplay(submenu)}
  linkyspan.onkeypress = function (e) { e = e || window.event; var key = e.keyCode || e.which; if (key == 13) { toogleDisplay(submenu); }; }
}