function dropdown(id){
  var menuEntries= document.getElementById(id).childNodes;
  for(var i = 0;i < menuEntries.length;i++){
    if(menuEntries[i].tagName == 'LI'){
      menuEntries[i].onmouseover = function () {show(this)};
      menuEntries[i].onmouseout = function () {hide(this)};
    }
  }
}
function show(obj)
{
  obj.className='show_sub';
}
function hide(obj)
{
  obj.className='';
}