function menuLinkMouseover(element_id)
{
		element_id.className  = "mainMenuItemMouseover";
}

function menuLinkMouseout(element_id)
{
		element_id.className  = "mainMenuItem";
}

function toggle_visibility(id)
{
  var e=document.getElementById(id);
  if(e.style.display=='none')
     e.style.display='block';
  else
     e.style.display='none';   
}