function openMenu(id)  { 
  var element = $(id);

  // First level
  if (element.id.substr(0,1) == "m") {
    updateMenuClassName(element);
    showSubMenu(element);
  }
  // First level
  if (element && element.id.substr(0,1) == "s") { 
    // Update menu class name
    openMenu(element.up().id)
    updateMenuClassName(element);         
    
    // Show sub menu   
    showSubMenu(element)
  } 
}   

function updateMenuClassName(element) {
  var menu  = element.firstDescendant();  
  var className = menu.className.replace("Slien_", "") + "_on";
  menu.className = className;      
}  
                                     
function showSubMenu(element) {   
  element.immediateDescendants().each(function(elt) {
    if (elt.tagName.toUpperCase() == "DIV")
      elt.show();
  })  
}