var menu = new Object();

function toggleSubmenus(sourceId) {
  if(menu[sourceId] == 1) {
    closeMenuItem(sourceId);
  } else {
    openMenuItem(sourceId);
  }
}
function openMenuItem(sourceId) {
  menu[sourceId] = 1;
  document.getElementById(sourceId+"_submenu").style.visibility = "visible";
  document.getElementById(sourceId+"_submenu").style.display = "block";
  document.getElementById(sourceId+"_pm").style.backgroundImage = "url('images/pm_minus.gif')";
}
function closeMenuItem(sourceId) {
  menu[sourceId] = 0;
  document.getElementById(sourceId+"_submenu").style.visibility = "hidden";
  document.getElementById(sourceId+"_submenu").style.display = "none";
  document.getElementById(sourceId+"_pm").style.backgroundImage = "url('images/pm_plus.gif')";
}